Commit graph

41 commits

Author SHA1 Message Date
Avi Kivity
c39cbd2a00 KVM: Document that KVM_GET_SUPPORTED_CPUID may return emulated values
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-10-24 10:52:48 +02:00
Alexander Graf
d1e87c7ee6 KVM: PPC: Add documentation for magic page enhancements
This documents how to detect additional features inside the magic
page when a guest maps it.

Signed-off-by: Alexander Graf <agraf@suse.de>
2010-10-24 10:52:22 +02:00
Alexander Graf
6f7a2bd41f KVM: PPC: Document KVM_INTERRUPT ioctl
This adds some documentation for the KVM_INTERRUPT special cases that
PowerPC now implements.

Signed-off-by: Alexander Graf <agraf@suse.de>
2010-10-24 10:52:20 +02:00
Alexander Graf
cbe487fac7 KVM: PPC: Add mtsrin PV code
This is the guest side of the mtsr acceleration. Using this a guest can now
call mtsrin with almost no overhead as long as it ensures that it only uses
it with (MSR_IR|MSR_DR) == 0. Linux does that, so we're good.

Signed-off-by: Alexander Graf <agraf@suse.de>
2010-10-24 10:52:12 +02:00
Zachary Amsden
f392eb2546 KVM: x86: Add timekeeping documentation
Basic informational document about x86 timekeeping and how KVM
is affected.

Signed-off-by: Zachary Amsden <zamsden@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-10-24 10:51:24 +02:00
Alexander Graf
15711e9c92 KVM: PPC: Add get_pvinfo interface to query hypercall instructions
We need to tell the guest the opcodes that make up a hypercall through
interfaces that are controlled by userspace. So we need to add a call
for userspace to allow it to query those opcodes so it can pass them
on.

This is required because the hypercall opcodes can change based on
the hypervisor conditions. If we're running in hardware accelerated
hypervisor mode, a hypercall looks different from when we're running
without hardware acceleration.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-10-24 10:50:57 +02:00
Alexander Graf
d7d3c2ea99 KVM: PPC: Add Documentation about PV interface
We just introduced a new PV interface that screams for documentation. So here
it is - a shiny new and awesome text file describing the internal works of
the PPC KVM paravirtual interface.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-10-24 10:50:57 +02:00
Avi Kivity
d153513dde KVM: Document KVM_GET_SUPPORTED_CPUID2 ioctl
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-08-02 06:40:50 +03:00
Avi Kivity
2e2602ca5d KVM: Document MCE banks non-exposure via KVM_GET_MSR_INDEX_LIST
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-08-02 06:40:38 +03:00
Avi Kivity
cf3e3d3e19 KVM: Document KVM specific review items
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-08-01 10:47:20 +03:00
Avi Kivity
b74a07beed KVM: Remove kernel-allocated memory regions
Equivalent (and better) functionality is provided by user-allocated memory
regions.

Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01 10:47:01 +03:00
Avi Kivity
a1f4d39500 KVM: Remove memory alias support
As advertised in feature-removal-schedule.txt.  Equivalent support is provided
by overlapping memory regions.

Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01 10:47:00 +03:00
Jason Wang
21bbe18b2d KVM: Fix typos in Documentation/kvm/mmu.txt
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-08-01 10:46:52 +03:00
Sheng Yang
2d5b5a6655 KVM: x86: XSAVE/XRSTOR live migration support
This patch enable save/restore of xsave state.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-08-01 10:46:37 +03:00
Glauber Costa
d2d7a61127 KVM: Add Documentation/kvm/msr.txt
This patch adds a file that documents the usage of KVM-specific
MSRs.

Signed-off-by: Glauber Costa <glommer@redhat.com>
Reviewed-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-08-01 10:39:24 +03:00
Avi Kivity
316b95216e KVM: MMU: Document large pages
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-08-01 10:39:23 +03:00
Avi Kivity
ec87fe2afc KVM: MMU: Document cr0.wp emulation
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01 10:39:23 +03:00
Lai Jiangshan
2032a93d66 KVM: MMU: Don't allocate gfns page for direct mmu pages
When sp->role.direct is set, sp->gfns does not contain any essential
information, leaf sptes reachable from this sp are for a continuous
guest physical memory range (a linear range).
So sp->gfns[i] (if it was set) equals to sp->gfn + i. (PT_PAGE_TABLE_LEVEL)
Obviously, it is not essential information, we can calculate it when need.

It means we don't need sp->gfns when sp->role.direct=1,
Thus we can save one page usage for every kvm_mmu_page.

Note:
  Access to sp->gfns must be wrapped by kvm_mmu_page_get_gfn()
  or kvm_mmu_page_set_gfn().
  It is only exposed in FNAME(sync_page).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01 10:35:52 +03:00
Gui Jianfeng
6859762e8a KVM: update mmu documetation for role.nxe
There's no member "cr4_nxe" in struct kvm_mmu_page_role, it names "nxe" now.
Update mmu document.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-08-01 10:35:41 +03:00
Avi Kivity
57bc24cfd6 KVM: Document KVM_SET_BOOT_CPU_ID
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01 10:35:40 +03:00
Avi Kivity
47dbb84f9e KVM: Document KVM_SET_IDENTITY_MAP ioctl
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-08-01 10:35:40 +03:00
Avi Kivity
3dbe141595 KVM: MMU: Segregate shadow pages with different cr0.wp
When cr0.wp=0, we may shadow a gpte having u/s=1 and r/w=0 with an spte
having u/s=0 and r/w=1.  This allows excessive access if the guest sets
cr0.wp=1 and accesses through this spte.

Fix by making cr0.wp part of the base role; we'll have different sptes for
the two cases and the problem disappears.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-05-19 11:41:09 +03:00
Glauber Costa
09c9e81366 KVM: Add cpuid.txt file
This file documents cpuid bits used by KVM.

Signed-off-by: Glauber Costa <glommer@redhat.com>
Acked-by: Zachary Amsden <zamsden@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-05-19 11:41:07 +03:00
Avi Kivity
c4bd09b289 KVM: Minor MMU documentation edits
Reported by Andrew Jones.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-05-17 12:19:32 +03:00
Avi Kivity
b843f06548 KVM: Document KVM_GET_MP_STATE and KVM_SET_MP_STATE
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-05-17 12:19:30 +03:00
Avi Kivity
039091875c KVM: Document mmu
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17 12:19:12 +03:00
Avi Kivity
647dc49eeb KVM: Document replacements for KVM_EXIT_HYPERCALL
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17 12:17:22 +03:00
Alexander Graf
ad0a048b09 KVM: PPC: Add OSI hypercall interface
MOL uses its own hypercall interface to call back into userspace when
the guest wants to do something.

So let's implement that as an exit reason, specify it with a CAP and
only really use it when userspace wants us to.

The only user of it so far is MOL.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17 12:17:10 +03:00
Alexander Graf
71fbfd5f38 KVM: Add support for enabling capabilities per-vcpu
Some times we don't want all capabilities to be available to all
our vcpus. One example for that is the OSI interface, implemented
in the next patch.

In order to have a generic mechanism in how to enable capabilities
individually, this patch introduces a new ioctl that can be used
for this purpose. That way features we don't want in all guests or
userspace configurations can just not be enabled and we're good.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17 12:17:09 +03:00
Avi Kivity
8a5416db83 KVM: Document KVM_SET_TSS_ADDR
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17 12:16:47 +03:00
Avi Kivity
0f2d8f4dd0 KVM: Document KVM_SET_USER_MEMORY_REGION
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-05-17 12:16:46 +03:00
Jan Kiszka
a1efbe77c1 KVM: x86: Add support for saving&restoring debug registers
So far user space was not able to save and restore debug registers for
migration or after reset. Plug this hole.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-04-25 12:39:10 +03:00
Jan Kiszka
48005f64d0 KVM: x86: Save&restore interrupt shadow mask
The interrupt shadow created by STI or MOV-SS-like operations is part of
the VCPU state and must be preserved across migration. Transfer it in
the spare padding field of kvm_vcpu_events.interrupt.

As a side effect we now have to make vmx_set_interrupt_shadow robust
against both shadow types being set. Give MOV SS a higher priority and
skip STI in that case to avoid that VMX throws a fault on next entry.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-04-25 12:38:28 +03:00
Marcelo Tosatti
679613442f KVM: add doc note about PIO/MMIO completion API
Document that partially emulated instructions leave the guest state
inconsistent, and that the kernel will complete operations before
checking for pending signals.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2010-04-25 12:26:32 +03:00
Wu Fengguang
2044892d4a KVM: trivial document fixes
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2010-03-01 12:35:43 -03:00
Jan Kiszka
dab4b911a5 KVM: x86: Extend KVM_SET_VCPU_EVENTS with selective updates
User space may not want to overwrite asynchronously changing VCPU event
states on write-back. So allow to skip nmi.pending and sipi_vector by
setting corresponding bits in the flags field of kvm_vcpu_events.

[avi: advertise the bits in KVM_GET_VCPU_EVENTS]

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-27 13:36:33 -02:00
Jan Kiszka
3cfc3092f4 KVM: x86: Add KVM_GET/SET_VCPU_EVENTS
This new IOCTL exports all yet user-invisible states related to
exceptions, interrupts, and NMIs. Together with appropriate user space
changes, this fixes sporadic problems of vmsave/restore, live migration
and system reset.

[avi: future-proof abi by adding a flags field]

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:25 +02:00
Glauber Costa
afbcf7ab8d KVM: allow userspace to adjust kvmclock offset
When we migrate a kvm guest that uses pvclock between two hosts, we may
suffer a large skew. This is because there can be significant differences
between the monotonic clock of the hosts involved. When a new host with
a much larger monotonic time starts running the guest, the view of time
will be significantly impacted.

Situation is much worse when we do the opposite, and migrate to a host with
a smaller monotonic clock.

This proposed ioctl will allow userspace to inform us what is the monotonic
clock value in the source host, so we can keep the time skew short, and
more importantly, never goes backwards. Userspace may also need to trigger
the current data, since from the first migration onwards, it won't be
reflected by a simple call to clock_gettime() anymore.

[marcelo: future-proof abi with a flags field]
[jan: fix KVM_GET_CLOCK by clearing flags field instead of checking it]

Signed-off-by: Glauber Costa <glommer@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:19 +02:00
Ed Swierk
ffde22ac53 KVM: Xen PV-on-HVM guest support
Support for Xen PV-on-HVM guests can be implemented almost entirely in
userspace, except for handling one annoying MSR that maps a Xen
hypercall blob into guest address space.

A generic mechanism to delegate MSR writes to userspace seems overkill
and risks encouraging similar MSR abuse in the future.  Thus this patch
adds special support for the Xen HVM MSR.

I implemented a new ioctl, KVM_XEN_HVM_CONFIG, that lets userspace tell
KVM which MSR the guest will write to, as well as the starting address
and size of the hypercall blobs (one each for 32-bit and 64-bit) that
userspace has loaded from files.  When the guest writes to the MSR, KVM
copies one page of the blob from userspace to the guest.

I've tested this patch with a hacked-up version of Gerd's userspace
code, booting a number of guests (CentOS 5.3 i386 and x86_64, and
FreeBSD 8.0-RC1 amd64) and exercising PV network and block devices.

[jan: fix i386 build warning]
[avi: future proof abi with a flags field]

Signed-off-by: Ed Swierk <eswierk@aristanetworks.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:18 +02:00
Avi Kivity
5dadbfd647 KVM: Document KVM_CAP_IRQCHIP
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 10:46:55 +03:00
Avi Kivity
9c1b96e347 KVM: Document basic API
Document the basic API corresponding to the 2.6.22 release.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-09-10 08:33:09 +03:00