Commit graph

327 commits

Author SHA1 Message Date
Jan H. Schönherr
20b7035c66 KVM: Let KVM_SET_SIGNAL_MASK work as advertised
KVM API says for the signal mask you set via KVM_SET_SIGNAL_MASK, that
"any unblocked signal received [...] will cause KVM_RUN to return with
-EINTR" and that "the signal will only be delivered if not blocked by
the original signal mask".

This, however, is only true, when the calling task has a signal handler
registered for a signal. If not, signal evaluation is short-circuited for
SIG_IGN and SIG_DFL, and the signal is either ignored without KVM_RUN
returning or the whole process is terminated.

Make KVM_SET_SIGNAL_MASK behave as advertised by utilizing logic similar
to that in do_sigtimedwait() to avoid short-circuiting of signals.

Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-11-27 17:53:47 +01:00
Greg Kroah-Hartman
b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Davidlohr Bueso
4c0b4bc60f kvm,mips: Fix potential swait_active() races
For example, the following could occur, making us miss a wakeup:

CPU0					CPU1
kvm_vcpu_block				kvm_mips_comparecount_func
					  [L] swait_active(&vcpu->wq)
  [S] prepare_to_swait(&vcpu->wq)
  [L] if (!kvm_vcpu_has_pending_timer(vcpu))
         schedule()                       [S] queue_timer_int(vcpu)

Ensure that the swait_active() check is not hoisted over the interrupt.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-09-15 16:57:13 +02:00
Longpeng(Mike)
199b5763d3 KVM: add spinlock optimization framework
If a vcpu exits due to request a user mode spinlock, then
the spinlock-holder may be preempted in user mode or kernel mode.
(Note that not all architectures trap spin loops in user mode,
only AMD x86 and ARM/ARM64 currently do).

But if a vcpu exits in kernel mode, then the holder must be
preempted in kernel mode, so we should choose a vcpu in kernel mode
as a more likely candidate for the lock holder.

This introduces kvm_arch_vcpu_in_kernel() to decide whether the
vcpu is in kernel-mode when it's preempted.  kvm_vcpu_on_spin's
new argument says the same of the spinning VCPU.

Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-08-08 10:57:43 +02:00
Linus Torvalds
c136b84393 PPC:
- Better machine check handling for HV KVM
 - Ability to support guests with threads=2, 4 or 8 on POWER9
 - Fix for a race that could cause delayed recognition of signals
 - Fix for a bug where POWER9 guests could sleep with interrupts pending.
 
 ARM:
 - VCPU request overhaul
 - allow timer and PMU to have their interrupt number selected from userspace
 - workaround for Cavium erratum 30115
 - handling of memory poisonning
 - the usual crop of fixes and cleanups
 
 s390:
 - initial machine check forwarding
 - migration support for the CMMA page hinting information
 - cleanups and fixes
 
 x86:
 - nested VMX bugfixes and improvements
 - more reliable NMI window detection on AMD
 - APIC timer optimizations
 
 Generic:
 - VCPU request overhaul + documentation of common code patterns
 - kvm_stat improvements
 
 There is a small conflict in arch/s390 due to an arch-wide field rename.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:
 "PPC:
   - Better machine check handling for HV KVM
   - Ability to support guests with threads=2, 4 or 8 on POWER9
   - Fix for a race that could cause delayed recognition of signals
   - Fix for a bug where POWER9 guests could sleep with interrupts pending.

  ARM:
   - VCPU request overhaul
   - allow timer and PMU to have their interrupt number selected from userspace
   - workaround for Cavium erratum 30115
   - handling of memory poisonning
   - the usual crop of fixes and cleanups

  s390:
   - initial machine check forwarding
   - migration support for the CMMA page hinting information
   - cleanups and fixes

  x86:
   - nested VMX bugfixes and improvements
   - more reliable NMI window detection on AMD
   - APIC timer optimizations

  Generic:
   - VCPU request overhaul + documentation of common code patterns
   - kvm_stat improvements"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (124 commits)
  Update my email address
  kvm: vmx: allow host to access guest MSR_IA32_BNDCFGS
  x86: kvm: mmu: use ept a/d in vmcs02 iff used in vmcs12
  kvm: x86: mmu: allow A/D bits to be disabled in an mmu
  x86: kvm: mmu: make spte mmio mask more explicit
  x86: kvm: mmu: dead code thanks to access tracking
  KVM: PPC: Book3S: Fix typo in XICS-on-XIVE state saving code
  KVM: PPC: Book3S HV: Close race with testing for signals on guest entry
  KVM: PPC: Book3S HV: Simplify dynamic micro-threading code
  KVM: x86: remove ignored type attribute
  KVM: LAPIC: Fix lapic timer injection delay
  KVM: lapic: reorganize restart_apic_timer
  KVM: lapic: reorganize start_hv_timer
  kvm: nVMX: Check memory operand to INVVPID
  KVM: s390: Inject machine check into the nested guest
  KVM: s390: Inject machine check into the guest
  tools/kvm_stat: add new interactive command 'b'
  tools/kvm_stat: add new command line switch '-i'
  tools/kvm_stat: fix error on interactive command 'g'
  KVM: SVM: suppress unnecessary NMI singlestep on GIF=0 and nested exit
  ...
2017-07-06 18:38:31 -07:00
James Cowgill
e27a9eca5d KVM: MIPS: Fix maybe-uninitialized build failure
This commit fixes a "maybe-uninitialized" build failure in
arch/mips/kvm/tlb.c when KVM, DYNAMIC_DEBUG and JUMP_LABEL are all
enabled. The failure is:

In file included from ./include/linux/printk.h:329:0,
                 from ./include/linux/kernel.h:13,
                 from ./include/asm-generic/bug.h:15,
                 from ./arch/mips/include/asm/bug.h:41,
                 from ./include/linux/bug.h:4,
                 from ./include/linux/thread_info.h:11,
                 from ./include/asm-generic/current.h:4,
                 from ./arch/mips/include/generated/asm/current.h:1,
                 from ./include/linux/sched.h:11,
                 from arch/mips/kvm/tlb.c:13:
arch/mips/kvm/tlb.c: In function ‘kvm_mips_host_tlb_inv’:
./include/linux/dynamic_debug.h:126:3: error: ‘idx_kernel’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
   __dynamic_pr_debug(&descriptor, pr_fmt(fmt), \
   ^~~~~~~~~~~~~~~~~~
arch/mips/kvm/tlb.c:169:16: note: ‘idx_kernel’ was declared here
  int idx_user, idx_kernel;
                ^~~~~~~~~~

There is a similar error relating to "idx_user". Both errors were
observed with GCC 6.

As far as I can tell, it is impossible for either idx_user or idx_kernel
to be uninitialized when they are later read in the calls to kvm_debug,
but to satisfy the compiler, add zero initializers to both variables.

Signed-off-by: James Cowgill <James.Cowgill@imgtec.com>
Fixes: 57e3869cfa ("KVM: MIPS/TLB: Generalise host TLB invalidate to kernel ASID")
Cc: <stable@vger.kernel.org> # 4.11+
Acked-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-06-20 17:02:48 +02:00
Radim Krčmář
2fa6e1e12a KVM: add kvm_request_pending
A first step in vcpu->requests encapsulation.  Additionally, we now
use READ_ONCE() when accessing vcpu->requests, which ensures we
always load vcpu->requests when it's accessed.  This is important as
other threads can change it any time.  Also, READ_ONCE() documents
that vcpu->requests is used with other threads, likely requiring
memory barriers, which it does.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
[ Documented the new use of READ_ONCE() and converted another check
  in arch/mips/kvm/vz.c ]
Signed-off-by: Andrew Jones <drjones@redhat.com>
Acked-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
2017-06-04 16:53:00 +02:00
Radim Krčmář
72875d8a4d KVM: add kvm_{test,clear}_request to replace {test,clear}_bit
Users were expected to use kvm_check_request() for testing and clearing,
but request have expanded their use since then and some users want to
only test or do a faster clear.

Make sure that requests are not directly accessed with bit operations.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-04-27 14:12:22 +02:00
Paolo Bonzini
3042255899 kvm: make KVM_CAP_COALESCED_MMIO architecture agnostic
Remove code from architecture files that can be moved to virt/kvm, since there
is already common code for coalesced MMIO.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
[Removed a pointless 'break' after 'return'.]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
2017-04-07 16:49:00 +02:00
James Hogan
dc44abd6aa KVM: MIPS/Emulate: Properly implement TLBR for T&E
Properly implement emulation of the TLBR instruction for Trap & Emulate.
This instruction reads the TLB entry pointed at by the CP0_Index
register into the other TLB registers, which may have the side effect of
changing the current ASID. Therefore abstract the CP0_EntryHi and ASID
changing code into a common function in the process.

A comment indicated that Linux doesn't use TLBR, which is true during
normal use, however dumping of the TLB does use it (for example with the
relatively recent 'x' magic sysrq key), as does a wired TLB entries test
case in my KVM tests.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 16:31:37 +01:00
James Hogan
1f48f9be4d KVM: MIPS/VZ: Handle Octeon III guest.PRid register
Octeon III implements a read-only guest CP0_PRid register, so add cases
to the KVM register access API for Octeon to ensure the correct value is
read and writes are ignored.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 15:36:20 +01:00
James Hogan
3ba731daf0 KVM: MIPS/VZ: Emulate hit CACHE ops for Octeon III
Octeon III doesn't implement the optional GuestCtl0.CG bit to allow
guest mode to execute virtual address based CACHE instructions, so
implement emulation of a few important ones specifically for Octeon III
in response to a GPSI exception.

Currently the main reason to perform these operations is for icache
synchronisation, so they are implemented as a simple icache flush with
local_flush_icache_range().

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 15:36:19 +01:00
James Hogan
824533ad16 KVM: MIPS/VZ: VZ hardware setup for Octeon III
Set up hardware virtualisation on Octeon III cores, configuring guest
interrupt routing and carving out half of the root TLB for guest use,
restoring it back again afterwards.

We need to be careful to inhibit TLB shutdown machine check exceptions
while invalidating guest TLB entries, since TLB invalidation is not
available so guest entries must be invalidated by setting them to unique
unmapped addresses, which could conflict with mappings set by the guest
or root if recently repartitioned.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 15:36:18 +01:00
James Hogan
867f4da752 KVM: MIPS/T&E: Report correct dcache line size
Octeon CPUs don't report the correct dcache line size in CP0_Config1.DL,
so encode the correct value for the guest CP0_Config1.DL based on
cpu_dcache_line_size().

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 15:36:18 +01:00
James Hogan
1c506c9c10 KVM: MIPS/TLB: Handle virtually tagged icaches
When TLB entries are invalidated in the presence of a virtually tagged
icache, such as that found on Octeon CPUs, flush the icache so that we
don't get a reserved instruction exception even though the TLB mapping
is removed.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 15:36:17 +01:00
James Hogan
4fa9de5a64 KVM: MIPS/Emulate: Adapt T&E CACHE emulation for Octeon
Cache management is implemented separately for Cavium Octeon CPUs, so
r4k_blast_[id]cache aren't available. Instead for Octeon perform a local
icache flush using local_flush_icache_range(), and for other platforms
which don't use c-r4k.c use __flush_cache_all() / flush_icache_all().

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 15:36:17 +01:00
James Hogan
edec9d7bdc KVM: MIPS/VZ: Trace guest mode changes
Create a trace event for guest mode changes, and enable VZ's
GuestCtl0.MC bit after the trace event is enabled to trap all guest mode
changes.

The MC bit causes Guest Hardware Field Change (GHFC) exceptions whenever
a guest mode change occurs (such as an exception entry or return from
exception), so we need to handle this exception now. The MC bit is only
enabled when restoring register state, so enabling the trace event won't
take immediate effect.

Tracing guest mode changes can be particularly handy when trying to work
out what a guest OS gets up to before something goes wrong, especially
if the problem occurs as a result of some previous guest userland
exception which would otherwise be invisible in the trace.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:54:00 +01:00
James Hogan
f4474d50c7 KVM: MIPS/VZ: Support hardware guest timer
Transfer timer state to the VZ guest context (CP0_GTOffset & guest
CP0_Count) when entering guest mode, enabling direct guest access to it,
and transfer back to soft timer when saving guest register state.

This usually allows guest code to directly read CP0_Count (via MFC0 and
RDHWR) and read/write CP0_Compare, without trapping to the hypervisor
for it to emulate the guest timer. Writing to CP0_Count or CP0_Cause.DC
is much less common and still triggers a hypervisor GPSI exception, in
which case the timer state is transferred back to an hrtimer before
emulating the write.

We are careful to prevent small amounts of drift from building up due to
undeterministic time intervals between reading of the ktime and reading
of CP0_Count. Some drift is expected however, since the system
clocksource may use a different timer to the local CP0_Count timer used
by VZ. This is permitted to prevent guest CP0_Count from appearing to go
backwards.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:59 +01:00
James Hogan
d42a008f86 KVM: MIPS/VZ: Emulate MAARs when necessary
Add emulation of Memory Accessibility Attribute Registers (MAARs) when
necessary. We can't actually do anything with whatever the guest
provides, but it may not be possible to clear Guest.Config5.MRP so we
have to emulate at least a pair of MAARs.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-doc@vger.kernel.org
2017-03-28 14:53:58 +01:00
James Hogan
273819a6a5 KVM: MIPS/VZ: Support guest load-linked bit
When restoring guest state after another VCPU has run, be sure to clear
CP0_LLAddr.LLB in order to break any interrupted atomic critical
section. Without this SMP guest atomics don't work when LLB is present
as one guest can complete the atomic section started by another guest.

MIPS VZ guest read of CP0_LLAddr causes Guest Privileged Sensitive
Instruction (GPSI) exception due to the address being root physical.
Handle this by reporting only the LLB bit, which contains the bit for
whether a ll/sc atomic is in progress without any reason for failure.

Similarly on P5600 a guest write to CP0_LLAddr also causes a GPSI
exception. Handle this also by clearing the guest LLB bit from root
mode.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:58 +01:00
James Hogan
5a2f352f34 KVM: MIPS/VZ: Support guest hardware page table walker
Add support for VZ guest CP0_PWBase, CP0_PWField, CP0_PWSize, and
CP0_PWCtl registers for controlling the guest hardware page table walker
(HTW) present on P5600 and P6600 cores. These guest registers need
initialising on R6, context switching, and exposing via the KVM ioctl
API when they are present.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-doc@vger.kernel.org
2017-03-28 14:53:57 +01:00
James Hogan
4b7de028e6 KVM: MIPS/VZ: Support guest segmentation control
Add support for VZ guest CP0_SegCtl0, CP0_SegCtl1, and CP0_SegCtl2
registers, as found on P5600 and P6600 cores. These guest registers need
initialising, context switching, and exposing via the KVM ioctl API when
they are present.

They also require the GVA -> GPA translation code for handling a GVA
root exception to be updated to interpret the segmentation registers and
decode the faulting instruction enough to detect EVA memory access
instructions.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-doc@vger.kernel.org
2017-03-28 14:53:56 +01:00
James Hogan
dffe042fd8 KVM: MIPS/VZ: Support guest CP0_[X]ContextConfig
Add support for VZ guest CP0_ContextConfig and CP0_XContextConfig
(MIPS64 only) registers, as found on P5600 and P6600 cores. These guest
registers need initialising, context switching, and exposing via the KVM
ioctl API when they are present.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-doc@vger.kernel.org
2017-03-28 14:53:56 +01:00
James Hogan
edc89260d4 KVM: MIPS/VZ: Support guest CP0_BadInstr[P]
Add support for VZ guest CP0_BadInstr and CP0_BadInstrP registers, as
found on most VZ capable cores. These guest registers need context
switching, and exposing via the KVM ioctl API when they are present.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-doc@vger.kernel.org
2017-03-28 14:53:55 +01:00
James Hogan
56f7a44050 KVM: MIPS: Add VZ support to build system
Add support for the MIPS Virtualization (VZ) ASE to the MIPS KVM build
system. For now KVM can only be configured for T&E or VZ and not both,
but the design of the user facing APIs support the possibility of having
both available, so this could change in future.

Note that support for various optional guest features (some of which
can't be turned off) are implemented in immediately following commits,
so although it should now be possible to build VZ support, it may not
work yet on your hardware.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:54 +01:00
James Hogan
c992a4f6a9 KVM: MIPS: Implement VZ support
Add the main support for the MIPS Virtualization ASE (A.K.A. VZ) to MIPS
KVM. The bulk of this work is in vz.c, with various new state and
definitions elsewhere.

Enough is implemented to be able to run on a minimal VZ core. Further
patches will fill out support for guest features which are optional or
can be disabled.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-doc@vger.kernel.org
2017-03-28 14:53:54 +01:00
James Hogan
ea1bdbf683 KVM: MIPS: Update exit handler for VZ
The general guest exit handler needs a few tweaks for VZ compared to
trap & emulate, which for now are made directly depending on
CONFIG_KVM_MIPS_VZ:

- There is no need to re-enable the hardware page table walker (HTW), as
  it can be left enabled during guest mode operation with VZ.

- There is no need to perform a privilege check, as any guest privilege
  violations should have already been detected by the hardware and
  triggered the appropriate guest exception.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:53 +01:00
James Hogan
60c7aa3320 KVM: MIPS/Emulate: Drop CACHE emulation for VZ
Ifdef out the trap & emulate CACHE instruction emulation functions for
VZ. We will provide separate CACHE instruction emulation in vz.c, and we
need to avoid linker errors due to the use of T&E specific MMU helpers.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:53 +01:00
James Hogan
5dee99b24e KVM: MIPS/Emulate: Update CP0_Compare emulation for VZ
Update emulation of guest writes to CP0_Compare for VZ. There are two
main differences compared to trap & emulate:

 - Writing to CP0_Compare in the VZ hardware guest context acks any
   pending timer, clearing CP0_Cause.TI. If we don't want an ack to take
   place we must carefully restore the TI bit if it was previously set.

 - Even with guest timer access disabled in CP0_GuestCtl0.GT, if the
   guest CP0_Count reaches the guest CP0_Compare the timer interrupt
   will assert. To prevent this we must set CP0_GTOffset to move the
   guest CP0_Count out of the way of the new guest CP0_Compare, either
   before or after depending on whether it is a forwards or backwards
   change.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:52 +01:00
James Hogan
372582a6c6 KVM: MIPS/TLB: Add VZ TLB management
Add functions for MIPS VZ TLB management to tlb.c.

kvm_vz_host_tlb_inv() will be used for invalidating root TLB entries
after GPA page tables have been modified due to a KVM page fault. It
arranges for a root GPA mapping to be flushed from the TLB, using the
gpa_mm ASID or the current GuestID to do the probe.

kvm_vz_local_flush_roottlb_all_guests() and
kvm_vz_local_flush_guesttlb_all() flush all TLB entries in the
corresponding TLB for guest mappings (GPA->RPA for root TLB with
GuestID, and all entries for guest TLB). They will be used when starting
a new GuestID cycle, when VZ hardware is enabled/disabled, and also when
switching to a guest when the guest TLB contents may be stale or belong
to a different VM.

kvm_vz_guest_tlb_lookup() converts a guest virtual address to a guest
physical address using the guest TLB. This will be used to decode guest
virtual addresses which are sometimes provided by VZ hardware in
CP0_BadVAddr for certain exceptions when the guest physical address is
unavailable.

kvm_vz_save_guesttlb() and kvm_vz_load_guesttlb() will be used to
preserve wired guest VTLB entries while a guest isn't running.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:51 +01:00
James Hogan
1934a3ad09 KVM: MIPS/Entry: Update entry code to support VZ
Update MIPS KVM entry code to support VZ:

 - We need to set GuestCtl0.GM while in guest mode.

 - For cores supporting GuestID, we need to set the root GuestID to
   match the main GuestID while in guest mode so that the root TLB
   refill handler writes the correct GuestID into the TLB.

 - For cores without GuestID where the root ASID dealiases RVA/GPA
   mappings, we need to load that ASID from the gpa_mm rather than the
   per-VCPU guest_kernel_mm or guest_user_mm, since the root TLB maps
   guest physical addresses. We also need to restore the normal process
   ASID on exit.

 - The normal linux process pgd needs restoring on exit, as we can't
   leave the GPA mappings active for kernel code.

 - GuestCtl0 needs saving on exit for the GExcCode field, as it may be
   clobbered if a preemption occurs.

We also need to move the TLB refill handler to the XTLB vector at offset
0x80 on 64-bit VZ kernels, as hardware will use Root.Status.KX to
determine whether a TLB refill or XTLB Refill exception is to be taken
on a root TLB miss from guest mode, and KX needs to be set for kernel
code to be able to access the 64-bit segments.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:51 +01:00
James Hogan
a27660f3e4 KVM: MIPS: Abstract guest CP0 register access for VZ
Abstract the MIPS KVM guest CP0 register access macros into inline
functions which are generated by macros. This allows them to be
generated differently for VZ, where they will usually need to access the
hardware guest CP0 context rather than the saved values in RAM.

Accessors for each individual register are generated using these macros:

 - __BUILD_KVM_*_SW() for registers which are not present in the VZ
   hardware guest context, so kvm_{read,write}_c0_guest_##name() will
   access the saved value in RAM regardless of whether VZ is enabled.

 - __BUILD_KVM_*_HW() for registers which are present in the VZ hardware
   guest context, so kvm_{read,write}_c0_guest_##name() will access the
   hardware register when VZ is enabled.

These build the underlying accessors using further macros:

 - __BUILD_KVM_*_SAVED() builds e.g. kvm_{read,write}_sw_gc0_##name()
   functions for accessing the saved versions of the registers in RAM.
   This is used for implementing the common
   kvm_{read,write}_c0_guest_##name() accessors with T&E where registers
   are always stored in RAM, but are also available with VZ HW registers
   to allow them to be accessed while saved.

 - __BUILD_KVM_*_VZ() builds e.g. kvm_{read,write}_vz_gc0_##name()
   functions for accessing the VZ hardware guest context registers
   directly. This is used for implementing the common
   kvm_{read,write}_c0_guest_##name() accessors with VZ.

 - __BUILD_KVM_*_WRAP() builds wrappers with different names, which
   allows the common kvm_{read,write}_c0_guest_##name() functions to be
   implemented using the VZ accessors while still having the SAVED
   accessors available too.

 - __BUILD_KVM_SAVE_VZ() builds functions for saving and restoring VZ
   hardware guest context register state to RAM, improving conciseness
   of VZ context saving and restoring.

Similar macros exist for generating modifiers (set, clear, change),
either with a normal unlocked read/modify/write, or using atomic LL/SC
sequences.

These changes change the types of 32-bit registers to u32 instead of
unsigned long, which requires some changes to printk() functions in MIPS
KVM.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:50 +01:00
James Hogan
28c1e762b0 KVM: MIPS: Add guest exit exception callback
Add a callback for MIPS KVM implementations to handle the VZ guest
exit exception. Currently the trap & emulate implementation contains a
stub which reports an internal error, but the callback will be used
properly by the VZ implementation.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:49 +01:00
James Hogan
edab4fe1f6 KVM: MIPS: Add hardware_{enable,disable} callback
Add an implementation callback for the kvm_arch_hardware_enable() and
kvm_arch_hardware_disable() architecture functions, with simple stubs
for trap & emulate. This is in preparation for VZ which will make use of
them.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:49 +01:00
James Hogan
607ef2fdeb KVM: MIPS: Add callback to check extension
Add an implementation callback for checking presence of KVM extensions.
This allows implementation specific extensions to be provided without
ifdefs in mips.c.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:48 +01:00
James Hogan
a517c1ad65 KVM: MIPS: Init timer frequency from callback
Currently the software emulated timer is initialised to a frequency of
100MHz by kvm_mips_init_count(), but this isn't suitable for VZ where
the frequency of the guest timer matches that of the host.

Add a count_hz argument so the caller can specify the default frequency,
and move the call from kvm_arch_vcpu_create() to the implementation
specific vcpu_setup() callback, so that VZ can specify a different
frequency.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:48 +01:00
James Hogan
a8a3c42677 KVM: MIPS: Add VZ & TE capabilities
Add new KVM_CAP_MIPS_VZ and KVM_CAP_MIPS_TE capabilities, and in order
to allow MIPS KVM to support VZ without confusing old users (which
expect the trap & emulate implementation), define and start checking
KVM_CREATE_VM type codes.

The codes available are:

 - KVM_VM_MIPS_TE = 0

   This is the current value expected from the user, and will create a
   VM using trap & emulate in user mode, confined to the user mode
   address space. This may in future become unavailable if the kernel is
   only configured to support VZ, in which case the EINVAL error will be
   returned and KVM_CAP_MIPS_TE won't be available even though
   KVM_CAP_MIPS_VZ is.

 - KVM_VM_MIPS_VZ = 1

   This can be provided when the KVM_CAP_MIPS_VZ capability is available
   to create a VM using VZ, with a fully virtualized guest virtual
   address space. If VZ support is unavailable in the kernel, the EINVAL
   error will be returned (although old kernels without the
   KVM_CAP_MIPS_VZ capability may well succeed and create a trap &
   emulate VM).

This is designed to allow the desired implementation (T&E vs VZ) to be
potentially chosen at runtime rather than being fixed in the kernel
configuration.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-doc@vger.kernel.org
2017-03-28 14:53:47 +01:00
James Hogan
a7244920d1 KVM: MIPS: Extend counters & events for VZ GExcCodes
Extend MIPS KVM stats counters and kvm_transition trace event codes to
cover hypervisor exceptions, which have their own GExcCode field in
CP0_GuestCtl0 with up to 32 hypervisor exception cause codes.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:46 +01:00
James Hogan
c58cf74179 KVM: MIPS: Update kvm_lose_fpu() for VZ
Update the implementation of kvm_lose_fpu() for VZ, where there is no
need to enable the FPU/MSA in the root context if the FPU/MSA state is
loaded but disabled in the guest context.

The trap & emulate implementation needs to disable FPU/MSA in the root
context when the guest disables them in order to catch the COP1 unusable
or MSA disabled exception when they're used and pass it on to the guest.

For VZ however as long as the context is loaded and enabled in the root
context, the guest can enable and disable it in the guest context
without the hypervisor having to do much, and will take guest exceptions
without hypervisor intervention if used without being enabled in the
guest context.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:45 +01:00
James Hogan
59d7814ab2 KVM: MIPS/Emulate: Implement 64-bit MMIO emulation
Implement additional MMIO emulation for MIPS64, including 64-bit
loads/stores, and 32-bit unsigned loads. These are only exposed on
64-bit VZ hosts.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:45 +01:00
James Hogan
8b48d5b75d KVM: MIPS/Emulate: De-duplicate MMIO emulation
Refactor MIPS KVM MMIO load/store emulation to reduce code duplication.
Each duplicate differed slightly anyway, and it will simplify adding
64-bit MMIO support for VZ.

kvm_mips_emulate_store() and kvm_mips_emulate_load() can now return
EMULATE_DO_MMIO (as possibly originally intended). We therefore stop
calling either of these from kvm_mips_emulate_inst(), which is now only
used by kvm_trap_emul_handle_cop_unusable() which is picky about return
values.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-03-28 14:53:44 +01:00
James Hogan
955d8dc3ee KVM: MIPS: Implement HYPCALL emulation
Emulate the HYPCALL instruction added in the VZ ASE and used by the MIPS
paravirtualised guest support that is already merged. The new hypcall.c
handles arguments and the return value. No actual hypercalls are yet
supported, but this still allows us to safely step over hypercalls and
set an error code in the return value for forward compatibility.

Non-zero HYPCALL codes are not handled.

We also document the hypercall ABI which asm/kvm_para.h uses.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Cc: linux-doc@vger.kernel.org
2017-03-28 14:53:33 +01:00
Ingo Molnar
174cd4b1e5 sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h>
Fix up affected files that include this signal functionality via sched.h.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:32 +01:00
Paolo Bonzini
460df4c1fc KVM: race-free exit from KVM_RUN without POSIX signals
The purpose of the KVM_SET_SIGNAL_MASK API is to let userspace "kick"
a VCPU out of KVM_RUN through a POSIX signal.  A signal is attached
to a dummy signal handler; by blocking the signal outside KVM_RUN and
unblocking it inside, this possible race is closed:

          VCPU thread                     service thread
   --------------------------------------------------------------
        check flag
                                          set flag
                                          raise signal
        (signal handler does nothing)
        KVM_RUN

However, one issue with KVM_SET_SIGNAL_MASK is that it has to take
tsk->sighand->siglock on every KVM_RUN.  This lock is often on a
remote NUMA node, because it is on the node of a thread's creator.
Taking this lock can be very expensive if there are many userspace
exits (as is the case for SMP Windows VMs without Hyper-V reference
time counter).

As an alternative, we can put the flag directly in kvm_run so that
KVM can see it:

          VCPU thread                     service thread
   --------------------------------------------------------------
                                          raise signal
        signal handler
          set run->immediate_exit
        KVM_RUN
          check run->immediate_exit

Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-02-17 12:27:37 +01:00
James Hogan
12ed1faece KVM: MIPS: Allow multiple VCPUs to be created
Increase the maximum number of MIPS KVM VCPUs to 8, and implement the
KVM_CAP_NR_VCPUS and KVM_CAP_MAX_CPUS capabilities which expose the
recommended and maximum number of VCPUs to userland. The previous
maximum of 1 didn't allow for any form of SMP guests.

We calculate the values similarly to ARM, recommending as many VCPUs as
there are CPUs online in the system. This will allow userland to know
how many VCPUs it is possible to create.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-02-03 15:21:34 +00:00
James Hogan
ad58d4d4a2 KVM: MIPS/T&E: Expose read-only CP0_IntCtl register
Expose the CP0_IntCtl register through the KVM register access API,
which is a required register since MIPS32r2. It is currently read-only
since the VS field isn't implemented due to lack of Config3.VInt or
Config3.VEIC.

It is implemented in trap_emul.c so that a VZ implementation can allow
writes.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-02-03 15:21:33 +00:00
James Hogan
013044cc65 KVM: MIPS/T&E: Expose CP0_EntryLo0/1 registers
Expose the CP0_EntryLo0 and CP0_EntryLo1 registers through the KVM
register access API. This is fairly straightforward for trap & emulate
since we don't support the RI and XI bits. For the sake of future
proofing (particularly for VZ) it is explicitly specified that the API
always exposes the 64-bit version of these registers (i.e. with the RI
and XI bits in bit positions 63 and 62 respectively), and they are
implemented in trap_emul.c rather than mips.c to allow them to be
implemented differently for VZ.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-02-03 15:21:32 +00:00
James Hogan
be67a0be94 KVM: MIPS/T&E: Default to reset vector
Set the default VCPU state closer to the architectural reset state, with
PC pointing at the reset vector (uncached PA 0x1fc00000, which for KVM
T&E is VA 0x5fc00000), and with CP0_Status.BEV and CP0_Status.ERL to 1.

Although QEMU at least will overwrite this state, it makes sense to do
this now that CP0_EBase is properly implemented to check BEV, and now
that we support a sparse GPA layout potentially with a boot ROM at GPA
0x1fc00000.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-02-03 15:21:31 +00:00
James Hogan
7801bbe1bd KVM: MIPS/T&E: Implement CP0_EBase register
The CP0_EBase register is a standard feature of MIPS32r2, so we should
always have been implementing it properly. However the register value
was ignored and wasn't exposed to userland.

Fix the emulation of exceptions and interrupts to use the value stored
in guest CP0_EBase, and fix the masks so that the top 3 bits (rather
than the standard 2) are fixed, so that it is always in the guest KSeg0
segment.

Also add CP0_EBASE to the KVM one_reg interface so it can be accessed by
userland, also allowing the CPU number field to be written (which isn't
permitted by the guest).

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-02-03 15:21:30 +00:00
James Hogan
654229a024 KVM: MIPS/T&E: Move CP0 register access into T&E
Access to various CP0 registers via the KVM register access API needs to
be implementation specific to allow restrictions to be made on changes,
for example when VZ guest registers aren't present, so move them all
into trap_emul.c in preparation for VZ.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
2017-02-03 15:21:30 +00:00