Commit graph

1059550 commits

Author SHA1 Message Date
Paolo Bonzini
5a213b9220 Merge branch 'topic/ppc-kvm' of https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux into HEAD
Fix conflicts between memslot overhaul and commit 511d25d6b7 ("KVM:
PPC: Book3S: Suppress warnings when allocating too big memory slots")
from the powerpc tree.
2021-12-19 15:27:21 +01:00
Eric Farman
812de04661 KVM: s390: Clarify SIGP orders versus STOP/RESTART
With KVM_CAP_S390_USER_SIGP, there are only five Signal Processor
orders (CONDITIONAL EMERGENCY SIGNAL, EMERGENCY SIGNAL, EXTERNAL CALL,
SENSE, and SENSE RUNNING STATUS) which are intended for frequent use
and thus are processed in-kernel. The remainder are sent to userspace
with the KVM_CAP_S390_USER_SIGP capability. Of those, three orders
(RESTART, STOP, and STOP AND STORE STATUS) have the potential to
inject work back into the kernel, and thus are asynchronous.

Let's look for those pending IRQs when processing one of the in-kernel
SIGP orders, and return BUSY (CC2) if one is in process. This is in
agreement with the Principles of Operation, which states that only one
order can be "active" on a CPU at a time.

Cc: stable@vger.kernel.org
Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20211213210550.856213-2-farman@linux.ibm.com
[borntraeger@linux.ibm.com: add stable tag]
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
2021-12-17 14:52:47 +01:00
Janosch Frank
3c724f1a1c s390: uv: Add offset comments to UV query struct and fix naming
Changes to the struct are easier to manage with offset comments so
let's add some. And now that we know that the last struct member has
the wrong name let's also fix this.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
2021-12-17 14:49:26 +01:00
Janis Schoetterl-Glausch
bad13799e0 KVM: s390: gaccess: Cleanup access to guest pages
Introduce a helper function for guest frame access.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-Id: <20211126164549.7046-4-scgl@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
2021-12-17 14:49:26 +01:00
Janis Schoetterl-Glausch
7faa543df1 KVM: s390: gaccess: Refactor access address range check
Do not round down the first address to the page boundary, just translate
it normally, which gives the value we care about in the first place.
Given this, translating a single address is just the special case of
translating a range spanning a single page.

Make the output optional, so the function can be used to just check a
range.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-Id: <20211126164549.7046-3-scgl@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
2021-12-17 14:49:26 +01:00
Janis Schoetterl-Glausch
416e7f0c9d KVM: s390: gaccess: Refactor gpa and length calculation
Improve readability by renaming the length variable and
not calculating the offset manually.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Message-Id: <20211126164549.7046-2-scgl@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
2021-12-17 14:23:25 +01:00
Marc Zyngier
9d8604b285 KVM: arm64: Rework kvm_pgtable initialisation
Ganapatrao reported that the kvm_pgtable->mmu pointer is more or
less hardcoded to the main S2 mmu structure, while the nested
code needs it to point to other instances (as we have one instance
per nested context).

Rework the initialisation of the kvm_pgtable structure so that
this assumtion doesn't hold true anymore. This requires some
minor changes to the order in which things are initialised
(the mmu->arch pointer being the critical one).

Reported-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Reviewed-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211129200150.351436-5-maz@kernel.org
2021-12-16 17:01:05 +00:00
Marc Zyngier
43d8ac2212 Merge branch kvm-arm64/pkvm-hyp-sharing into kvmarm-master/next
* kvm-arm64/pkvm-hyp-sharing:
  : .
  : Series from Quentin Perret, implementing HYP page share/unshare:
  :
  : This series implements an unshare hypercall at EL2 in nVHE
  : protected mode, and makes use of it to unmmap guest-specific
  : data-structures from EL2 stage-1 during guest tear-down.
  : Crucially, the implementation of the share and unshare
  : routines use page refcounts in the host kernel to avoid
  : accidentally unmapping data-structures that overlap a common
  : page.
  : [...]
  : .
  KVM: arm64: pkvm: Unshare guest structs during teardown
  KVM: arm64: Expose unshare hypercall to the host
  KVM: arm64: Implement do_unshare() helper for unsharing memory
  KVM: arm64: Implement __pkvm_host_share_hyp() using do_share()
  KVM: arm64: Implement do_share() helper for sharing memory
  KVM: arm64: Introduce wrappers for host and hyp spin lock accessors
  KVM: arm64: Extend pkvm_page_state enumeration to handle absent pages
  KVM: arm64: pkvm: Refcount the pages shared with EL2
  KVM: arm64: Introduce kvm_share_hyp()
  KVM: arm64: Implement kvm_pgtable_hyp_unmap() at EL2
  KVM: arm64: Hook up ->page_count() for hypervisor stage-1 page-table
  KVM: arm64: Fixup hyp stage-1 refcount
  KVM: arm64: Refcount hyp stage-1 pgtable pages
  KVM: arm64: Provide {get,put}_page() stubs for early hyp allocator

Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-12-16 13:06:09 +00:00
Quentin Perret
52b28657eb KVM: arm64: pkvm: Unshare guest structs during teardown
Make use of the newly introduced unshare hypercall during guest teardown
to unmap guest-related data structures from the hyp stage-1.

Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-15-qperret@google.com
2021-12-16 12:58:57 +00:00
Will Deacon
b8cc6eb5bd KVM: arm64: Expose unshare hypercall to the host
Introduce an unshare hypercall which can be used to unmap memory from
the hypervisor stage-1 in nVHE protected mode. This will be useful to
update the EL2 ownership state of pages during guest teardown, and
avoids keeping dangling mappings to unreferenced portions of memory.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-14-qperret@google.com
2021-12-16 12:58:57 +00:00
Will Deacon
376a240f03 KVM: arm64: Implement do_unshare() helper for unsharing memory
Tearing down a previously shared memory region results in the borrower
losing access to the underlying pages and returning them to the "owned"
state in the owner.

Implement a do_unshare() helper, along the same lines as do_share(), to
provide this functionality for the host-to-hyp case.

Reviewed-by: Andrew Walbran <qwandor@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-13-qperret@google.com
2021-12-16 12:58:57 +00:00
Will Deacon
1ee32109fd KVM: arm64: Implement __pkvm_host_share_hyp() using do_share()
__pkvm_host_share_hyp() shares memory between the host and the
hypervisor so implement it as an invocation of the new do_share()
mechanism.

Note that double-sharing is no longer permitted (as this allows us to
reduce the number of page-table walks significantly), but is thankfully
no longer relied upon by the host.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-12-qperret@google.com
2021-12-16 12:58:57 +00:00
Will Deacon
e82edcc75c KVM: arm64: Implement do_share() helper for sharing memory
By default, protected KVM isolates memory pages so that they are
accessible only to their owner: be it the host kernel, the hypervisor
at EL2 or (in future) the guest. Establishing shared-memory regions
between these components therefore involves a transition for each page
so that the owner can share memory with a borrower under a certain set
of permissions.

Introduce a do_share() helper for safely sharing a memory region between
two components. Currently, only host-to-hyp sharing is implemented, but
the code is easily extended to handle other combinations and the
permission checks for each component are reusable.

Reviewed-by: Andrew Walbran <qwandor@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-11-qperret@google.com
2021-12-16 12:58:57 +00:00
Will Deacon
61d99e33e7 KVM: arm64: Introduce wrappers for host and hyp spin lock accessors
In preparation for adding additional locked sections for manipulating
page-tables at EL2, introduce some simple wrappers around the host and
hypervisor locks so that it's a bit easier to read and bit more difficult
to take the wrong lock (or even take them in the wrong order).

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-10-qperret@google.com
2021-12-16 12:58:57 +00:00
Will Deacon
3d467f7b8c KVM: arm64: Extend pkvm_page_state enumeration to handle absent pages
Explicitly name the combination of SW0 | SW1 as reserved in the pte and
introduce a new PKVM_NOPAGE meta-state which, although not directly
stored in the software bits of the pte, can be used to represent an
entry for which there is no underlying page. This is distinct from an
invalid pte, as stage-2 identity mappings for the host are created
lazily and so an invalid pte there is the same as a valid mapping for
the purposes of ownership information.

This state will be used for permission checking during page transitions
in later patches.

Reviewed-by: Andrew Walbran <qwandor@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-9-qperret@google.com
2021-12-16 12:58:56 +00:00
Quentin Perret
a83e2191b7 KVM: arm64: pkvm: Refcount the pages shared with EL2
In order to simplify the page tracking infrastructure at EL2 in nVHE
protected mode, move the responsibility of refcounting pages that are
shared multiple times on the host. In order to do so, let's create a
red-black tree tracking all the PFNs that have been shared, along with
a refcount.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-8-qperret@google.com
2021-12-16 12:58:56 +00:00
Quentin Perret
3f868e142c KVM: arm64: Introduce kvm_share_hyp()
The create_hyp_mappings() function can currently be called at any point
in time. However, its behaviour in protected mode changes widely
depending on when it is being called. Prior to KVM init, it is used to
create the temporary page-table used to bring-up the hypervisor, and
later on it is transparently turned into a 'share' hypercall when the
kernel has lost control over the hypervisor stage-1. In order to prepare
the ground for also unsharing pages with the hypervisor during guest
teardown, introduce a kvm_share_hyp() function to make it clear in which
places a share hypercall should be expected, as we will soon need a
matching unshare hypercall in all those places.

Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-7-qperret@google.com
2021-12-16 12:58:56 +00:00
Will Deacon
82bb02445d KVM: arm64: Implement kvm_pgtable_hyp_unmap() at EL2
Implement kvm_pgtable_hyp_unmap() which can be used to remove hypervisor
stage-1 mappings at EL2.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-6-qperret@google.com
2021-12-16 12:58:56 +00:00
Will Deacon
34ec7cbf1e KVM: arm64: Hook up ->page_count() for hypervisor stage-1 page-table
kvm_pgtable_hyp_unmap() relies on the ->page_count() function callback
being provided by the memory-management operations for the page-table.

Wire up this callback for the hypervisor stage-1 page-table.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-5-qperret@google.com
2021-12-16 12:58:56 +00:00
Quentin Perret
d6b4bd3f48 KVM: arm64: Fixup hyp stage-1 refcount
In nVHE-protected mode, the hyp stage-1 page-table refcount is broken
due to the lack of refcount support in the early allocator. Fix-up the
refcount in the finalize walker, once the 'hyp_vmemmap' is up and running.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-4-qperret@google.com
2021-12-16 12:58:56 +00:00
Quentin Perret
2ea2ff91e8 KVM: arm64: Refcount hyp stage-1 pgtable pages
To prepare the ground for allowing hyp stage-1 mappings to be removed at
run-time, update the KVM page-table code to maintain a correct refcount
using the ->{get,put}_page() function callbacks.

Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-3-qperret@google.com
2021-12-16 12:58:55 +00:00
Quentin Perret
1fac3cfb9c KVM: arm64: Provide {get,put}_page() stubs for early hyp allocator
In nVHE protected mode, the EL2 code uses a temporary allocator during
boot while re-creating its stage-1 page-table. Unfortunately, the
hyp_vmmemap is not ready to use at this stage, so refcounting pages
is not possible. That is not currently a problem because hyp stage-1
mappings are never removed, which implies refcounting of page-table
pages is unnecessary.

In preparation for allowing hypervisor stage-1 mappings to be removed,
provide stub implementations for {get,put}_page() in the early allocator.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211215161232.1480836-2-qperret@google.com
2021-12-16 12:58:55 +00:00
Marc Zyngier
ce5b5b05c1 Merge branch kvm-arm64/vgic-fixes-5.17 into kvmarm-master/next
* kvm-arm64/vgic-fixes-5.17:
  : .
  : A few vgic fixes:
  : - Harden vgic-v3 error handling paths against signed vs unsigned
  :   comparison that will happen once the xarray-based vcpus are in
  : - Demote userspace-triggered console output to kvm_debug()
  : .
  KVM: arm64: vgic: Demote userspace-triggered console prints to kvm_debug()
  KVM: arm64: vgic-v3: Fix vcpu index comparison

Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-12-16 12:54:12 +00:00
Marc Zyngier
440523b92b KVM: arm64: vgic: Demote userspace-triggered console prints to kvm_debug()
Running the KVM selftests results in these messages being dumped
in the kernel console:

[  188.051073] kvm [469]: VGIC redist and dist frames overlap
[  188.056820] kvm [469]: VGIC redist and dist frames overlap
[  188.076199] kvm [469]: VGIC redist and dist frames overlap

Being amle to trigger this from userspace is definitely not on,
so demote these warnings to kvm_debug().

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211216104507.1482017-1-maz@kernel.org
2021-12-16 10:47:48 +00:00
Marc Zyngier
c95b1d7ca7 KVM: arm64: vgic-v3: Fix vcpu index comparison
When handling an error at the point where we try and register
all the redistributors, we unregister all the previously
registered frames by counting down from the failing index.

However, the way the code is written relies on that index
being a signed value. Which won't be true once we switch to
an xarray-based vcpu set.

Since this code is pretty awkward the first place, and that the
failure mode is hard to spot, rewrite this loop to iterate
over the vcpus upwards rather than downwards.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211216104526.1482124-1-maz@kernel.org
2021-12-16 10:47:24 +00:00
Marc Zyngier
7b6871f670 Merge branch kvm-arm64/pkvm-cleanups-5.17 into kvmarm-master/next
* kvm-arm64/pkvm-cleanups-5.17:
  : .
  : pKVM cleanups from Quentin Perret:
  :
  : This series is a collection of various fixes and cleanups for KVM/arm64
  : when running in nVHE protected mode. The first two patches are real
  : fixes/improvements, the following two are minor cleanups, and the last
  : two help satisfy my paranoia so they're certainly optional.
  : .
  KVM: arm64: pkvm: Make kvm_host_owns_hyp_mappings() robust to VHE
  KVM: arm64: pkvm: Stub io map functions
  KVM: arm64: Make __io_map_base static
  KVM: arm64: Make the hyp memory pool static
  KVM: arm64: pkvm: Disable GICv2 support
  KVM: arm64: pkvm: Fix hyp_pool max order

Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-12-15 14:21:23 +00:00
Quentin Perret
64a1fbda59 KVM: arm64: pkvm: Make kvm_host_owns_hyp_mappings() robust to VHE
The kvm_host_owns_hyp_mappings() function should return true if and only
if the host kernel is responsible for creating the hypervisor stage-1
mappings. That is only possible in standard non-VHE mode, or during boot
in protected nVHE mode. But either way, none of this makes sense in VHE,
so make sure to catch this case as well, hence making the function
return sensible values in any context (VHE or not).

Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211208152300.2478542-7-qperret@google.com
2021-12-15 14:18:31 +00:00
Quentin Perret
bff01cb6b1 KVM: arm64: pkvm: Stub io map functions
Now that GICv2 is disabled in nVHE protected mode there should be no
other reason for the host to use create_hyp_io_mappings() or
kvm_phys_addr_ioremap(). Add sanity checks to make sure that assumption
remains true looking forward.

Signed-off-by: Quentin Perret <qperret@google.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211208152300.2478542-6-qperret@google.com
2021-12-15 14:17:31 +00:00
Quentin Perret
473a3efbaf KVM: arm64: Make __io_map_base static
The __io_map_base variable is used at EL2 to track the end of the
hypervisor's "private" VA range in nVHE protected mode. However it
doesn't need to be used outside of mm.c, so let's make it static to keep
all the hyp VA allocation logic in one place.

Signed-off-by: Quentin Perret <qperret@google.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211208152300.2478542-5-qperret@google.com
2021-12-15 14:17:30 +00:00
Quentin Perret
53a563b01f KVM: arm64: Make the hyp memory pool static
The hyp memory pool struct is sized to fit exactly the needs of the
hypervisor stage-1 page-table allocator, so it is important it is not
used for anything else. As it is currently used only from setup.c,
reduce its visibility by marking it static.

Signed-off-by: Quentin Perret <qperret@google.com>
Reviewed-by: Andrew Walbran <qwandor@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211208152300.2478542-4-qperret@google.com
2021-12-15 14:17:01 +00:00
Quentin Perret
a770ee80e6 KVM: arm64: pkvm: Disable GICv2 support
GICv2 requires having device mappings in guests and the hypervisor,
which is incompatible with the current pKVM EL2 page ownership model
which only covers memory. While it would be desirable to support pKVM
with GICv2, this will require a lot more work, so let's make the
current assumption clear until then.

Co-developed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211208152300.2478542-3-qperret@google.com
2021-12-15 14:16:28 +00:00
Quentin Perret
34b43a8849 KVM: arm64: pkvm: Fix hyp_pool max order
The EL2 page allocator in protected mode maintains a per-pool max order
value to optimize allocations when the memory region it covers is small.
However, the max order value is currently under-estimated whenever the
number of pages in the region is a power of two. Fix the estimation.

Signed-off-by: Quentin Perret <qperret@google.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211208152300.2478542-2-qperret@google.com
2021-12-15 14:16:28 +00:00
Sean Christopherson
63fa47ba88 KVM: PPC: Book3S HV P9: Use kvm_arch_vcpu_get_wait() to get rcuwait object
Use kvm_arch_vcpu_get_wait() to get a vCPU's rcuwait object instead of
using vcpu->wait directly in kvmhv_run_single_vcpu().  Functionally, this
is a nop as vcpu->arch.waitp is guaranteed to point at vcpu->wait.  But
that is not obvious at first glance, and a future change coming in via
the KVM tree, commit 510958e997 ("KVM: Force PPC to define its own
rcuwait object"), will hide vcpu->wait from architectures that define
__KVM_HAVE_ARCH_WQP to prevent generic KVM from attepting to wake a vCPU
with the wrong rcuwait object.

Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211213174556.3871157-1-seanjc@google.com
2021-12-14 22:49:36 +11:00
Sean Christopherson
10e7a099bf selftests: KVM: Add test to verify KVM doesn't explode on "bad" I/O
Add an x86 selftest to verify that KVM doesn't WARN or otherwise explode
if userspace modifies RCX during a userspace exit to handle string I/O.
This is a regression test for a user-triggerable WARN introduced by
commit 3b27de2718 ("KVM: x86: split the two parts of emulator_pio_in").

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211025201311.1881846-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-10 09:38:02 -05:00
Sean Christopherson
d07898eaf3 KVM: x86: Don't WARN if userspace mucks with RCX during string I/O exit
Replace a WARN with a comment to call out that userspace can modify RCX
during an exit to userspace to handle string I/O.  KVM doesn't actually
support changing the rep count during an exit, i.e. the scenario can be
ignored, but the WARN needs to go as it's trivial to trigger from
userspace.

Cc: stable@vger.kernel.org
Fixes: 3b27de2718 ("KVM: x86: split the two parts of emulator_pio_in")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211025201311.1881846-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-10 09:38:02 -05:00
Lai Jiangshan
777ab82d7c KVM: X86: Raise #GP when clearing CR0_PG in 64 bit mode
In the SDM:
If the logical processor is in 64-bit mode or if CR4.PCIDE = 1, an
attempt to clear CR0.PG causes a general-protection exception (#GP).
Software should transition to compatibility mode and clear CR4.PCIDE
before attempting to disable paging.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211207095230.53437-1-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-10 09:38:01 -05:00
Paolo Bonzini
c8cc43c1ea selftests: KVM: avoid failures due to reserved HyperTransport region
AMD proceessors define an address range that is reserved by HyperTransport
and causes a failure if used for guest physical addresses.  Avoid
selftests failures by reserving those guest physical addresses; the
rules are:

- On parts with <40 bits, its fully hidden from software.

- Before Fam17h, it was always 12G just below 1T, even if there was more
RAM above this location.  In this case we just not use any RAM above 1T.

- On Fam17h and later, it is variable based on SME, and is either just
below 2^48 (no encryption) or 2^43 (encryption).

Fixes: ef4c9f4f65 ("KVM: selftests: Fix 32-bit truncation of vm_get_max_gfn()")
Cc: stable@vger.kernel.org
Cc: David Matlack <dmatlack@google.com>
Reported-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210805105423.412878-1-pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Tested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-10 07:42:20 -05:00
Sean Christopherson
3244867af8 KVM: x86: Ignore sparse banks size for an "all CPUs", non-sparse IPI req
Do not bail early if there are no bits set in the sparse banks for a
non-sparse, a.k.a. "all CPUs", IPI request.  Per the Hyper-V spec, it is
legal to have a variable length of '0', e.g. VP_SET's BankContents in
this case, if the request can be serviced without the extra info.

  It is possible that for a given invocation of a hypercall that does
  accept variable sized input headers that all the header input fits
  entirely within the fixed size header. In such cases the variable sized
  input header is zero-sized and the corresponding bits in the hypercall
  input should be set to zero.

Bailing early results in KVM failing to send IPIs to all CPUs as expected
by the guest.

Fixes: 214ff83d44 ("KVM: x86: hyperv: implement PV IPI send hypercalls")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211207220926.718794-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-10 07:12:42 -05:00
Vitaly Kuznetsov
1ebfaa11eb KVM: x86: Wait for IPIs to be delivered when handling Hyper-V TLB flush hypercall
Prior to commit 0baedd7927 ("KVM: x86: make Hyper-V PV TLB flush use
tlb_flush_guest()"), kvm_hv_flush_tlb() was using 'KVM_REQ_TLB_FLUSH |
KVM_REQUEST_NO_WAKEUP' when making a request to flush TLBs on other vCPUs
and KVM_REQ_TLB_FLUSH is/was defined as:

 (0 | KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)

so KVM_REQUEST_WAIT was lost. Hyper-V TLFS, however, requires that
"This call guarantees that by the time control returns back to the
caller, the observable effects of all flushes on the specified virtual
processors have occurred." and without KVM_REQUEST_WAIT there's a small
chance that the vCPU making the TLB flush will resume running before
all IPIs get delivered to other vCPUs and a stale mapping can get read
there.

Fix the issue by adding KVM_REQUEST_WAIT flag to KVM_REQ_TLB_FLUSH_GUEST:
kvm_hv_flush_tlb() is the sole caller which uses it for
kvm_make_all_cpus_request()/kvm_make_vcpus_request_mask() where
KVM_REQUEST_WAIT makes a difference.

Cc: stable@kernel.org
Fixes: 0baedd7927 ("KVM: x86: make Hyper-V PV TLB flush use tlb_flush_guest()")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211209102937.584397-1-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-10 07:12:41 -05:00
David Woodhouse
d8f6ef45a6 KVM: arm64: Use Makefile.kvm for common files
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Marc Zyngier <maz@kernel.org>
Message-Id: <20211121125451.9489-8-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-09 13:06:19 -05:00
David Woodhouse
5f33868af8 KVM: powerpc: Use Makefile.kvm for common files
It's all fairly baroque but in the end, I don't think there's any reason
for $(KVM)/irqchip.o to have been handled differently, as they all end
up in $(kvm-y) in the end anyway, regardless of whether they get there
via $(common-objs-y) and the CPU-specific object lists.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Message-Id: <20211121125451.9489-7-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-09 13:06:01 -05:00
David Woodhouse
3e3aa26fd4 KVM: RISC-V: Use Makefile.kvm for common files
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20211121125451.9489-6-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-09 12:59:08 -05:00
David Woodhouse
ae1b606e62 KVM: mips: Use Makefile.kvm for common files
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20211121125451.9489-5-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-09 12:58:37 -05:00
David Woodhouse
f786ab1bf1 KVM: s390: Use Makefile.kvm for common files
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-Id: <20211121125451.9489-4-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-09 12:58:33 -05:00
David Woodhouse
6f2cdbdba4 KVM: Add Makefile.kvm for common files, use it for x86
Splitting kvm_main.c out into smaller and better-organized files is
slightly non-trivial when it involves editing a bunch of per-arch
KVM makefiles. Provide virt/kvm/Makefile.kvm for them to include.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Marc Zyngier <maz@kernel.org>
Message-Id: <20211121125451.9489-3-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-09 12:56:02 -05:00
David Woodhouse
dc70ec217c KVM: Introduce CONFIG_HAVE_KVM_DIRTY_RING
I'd like to make the build include dirty_ring.c based on whether the
arch wants it or not. That's a whole lot simpler if there's a config
symbol instead of doing it implicitly on KVM_DIRTY_LOG_PAGE_OFFSET
being set to something non-zero.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <20211121125451.9489-2-dwmw2@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-09 12:55:52 -05:00
Maciej S. Szmigiero
ee3a4f6662 KVM: x86: selftests: svm_int_ctl_test: fix intercept calculation
INTERCEPT_x are bit positions, but the code was using the raw value of
INTERCEPT_VINTR (4) instead of BIT(INTERCEPT_VINTR).
This resulted in masking of bit 2 - that is, SMI instead of VINTR.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Message-Id: <49b9571d25588870db5380b0be1a41df4bbaaf93.1638486479.git.maciej.szmigiero@oracle.com>
2021-12-09 12:44:39 -05:00
Sean Christopherson
45af1bb99b KVM: VMX: Clean up PI pre/post-block WARNs
Move the WARN sanity checks out of the PI descriptor update loop so as
not to spam the kernel log if the condition is violated and the update
takes multiple attempts due to another writer.  This also eliminates a
few extra uops from the retry path.

Technically not checking every attempt could mean KVM will now fail to
WARN in a scenario that would have failed before, but any such failure
would be inherently racy as some other agent (CPU or device) would have
to concurrent modify the PI descriptor.

Add a helper to handle the actual write and more importantly to document
why the write may need to be retried.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211208015236.1616697-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-09 09:30:47 -05:00
Sean Christopherson
83c98007d9 KVM: nVMX: Ensure vCPU honors event request if posting nested IRQ fails
Add a memory barrier between writing vcpu->requests and reading
vcpu->guest_mode to ensure the read is ordered after the write when
(potentially) delivering an IRQ to L2 via nested posted interrupt.  If
the request were to be completed after reading vcpu->mode, it would be
possible for the target vCPU to enter the guest without posting the
interrupt and without handling the event request.

Note, the barrier is only for documentation since atomic operations are
serializing on x86.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Fixes: 6b6977117f ("KVM: nVMX: Fix races when sending nested PI while dest enters/leaves L2")
Fixes: 705699a139 ("KVM: nVMX: Enable nested posted interrupt processing")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211208015236.1616697-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-09 09:30:46 -05:00
Maxim Levitsky
8e819d75cb KVM: x86: add a tracepoint for APICv/AVIC interrupt delivery
This allows to see how many interrupts were delivered via the
APICv/AVIC from the host.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20211209115440.394441-3-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-12-09 09:07:39 -05:00