[GIT PULL] KVM: x86: Two KVM fixes and a selftest fix

[GIT PULL] KVM: x86: Two KVM fixes and a selftest fix

[Sean Christopherson]

Please pull a few small KVM x86 fixes, along with a rather ugly selftest
fix to resolve a collision with linux/overflow.h.  Sadly, my attempt at a
less ugly fix fell flat, as trying to share linux/overflow.h's definition
doesn't work since not all selftests add tools/include to their include path.

Unrelated to this pull request, shameless plug for the guest_memfd mmap()
series[1].  We'd like to get it merged sooner than later as there's a bit of a
logjam of guest_memfd code piling up.  And I've promised others I'll yolo it
into kvm-x86 at the end of next week if necessary :-)

Thanks!

P.S. the guest_memfd mmap() series needs one minor fixup in patch 23[2]:

diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
index b86bf89a71e0..b3ca6737f304 100644
--- a/tools/testing/selftests/kvm/guest_memfd_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_test.c
@@ -372,7 +372,7 @@ int main(int argc, char *argv[])
         */
        vm_types = kvm_check_cap(KVM_CAP_VM_TYPES);
        if (!vm_types)
-               vm_types = VM_TYPE_DEFAULT;
+               vm_types = BIT(VM_TYPE_DEFAULT);
 
        for_each_set_bit(vm_type, &vm_types, BITS_PER_TYPE(vm_types))
                test_guest_memfd(vm_type);

[1] https://lore.kernel.org/all/20250729225455.670324-1-seanjc@google.com
[2] https://lore.kernel.org/all/aIoWosN3UiPe2qQK@google.com


The following changes since commit 8f5ae30d69d7543eee0d70083daf4de8fe15d585:

  Linux 6.17-rc1 (2025-08-10 19:41:16 +0300)

are available in the Git repository at:

  https://github.com/kvm-x86/linux.git tags/kvm-x86-fixes-6.17-rc7

for you to fetch changes up to dce1b33ed7430c7189b8cc1567498f9e6bf12731:

  selftests: harness: Rename is_signed_type() to avoid collision with overflow.h (2025-08-20 08:04:09 -0700)

----------------------------------------------------------------
KVM x86 fixes and a selftest fix for 6.17-rcN

 - Use array_index_nospec() to sanitize the target vCPU ID when handling PV
   IPIs and yields as the ID is guest-controlled.

 - Drop a superfluous cpumask_empty() check when reclaiming SEV memory, as
   the common case, by far, is that at least one CPU will have entered the
   VM, and wbnoinvd_on_cpus_mask() will naturally handle the rare case where
   the set of have_run_cpus is empty.

 - Rename the is_signed_type() macro in kselftest_harness.h to is_signed_var()
   to fix a collision with linux/overflow.h.  The collision generates compiler
   warnings due to the two macros having different implementations.

----------------------------------------------------------------
Sean Christopherson (1):
      selftests: harness: Rename is_signed_type() to avoid collision with overflow.h

Thijs Raymakers (1):
      KVM: x86: use array_index_nospec with indices that come from guest

Yury Norov (1):
      KVM: SEV: don't check have_run_cpus in sev_writeback_caches()

 arch/x86/kvm/lapic.c                        |  2 ++
 arch/x86/kvm/svm/sev.c                      | 10 +++-------
 arch/x86/kvm/x86.c                          |  7 +++++--
 tools/testing/selftests/kselftest_harness.h |  4 ++--
 4 files changed, 12 insertions(+), 11 deletions(-)

Re: [GIT PULL] KVM: x86: Two KVM fixes and a selftest fix

[Paolo Bonzini]

On Thu, Aug 21, 2025 at 11:31 PM Sean Christopherson <seanjc@google.com> wrote:
>
> Please pull a few small KVM x86 fixes, along with a rather ugly selftest
> fix to resolve a collision with linux/overflow.h.  Sadly, my attempt at a
> less ugly fix fell flat, as trying to share linux/overflow.h's definition
> doesn't work since not all selftests add tools/include to their include path.

Yes, I saw that from afar.

> Unrelated to this pull request, shameless plug for the guest_memfd mmap()
> series[1].  We'd like to get it merged sooner than later as there's a bit of a
> logjam of guest_memfd code piling up.  And I've promised others I'll yolo it
> into kvm-x86 at the end of next week if necessary :-)

Will pull it right after this one. Thanks!

Paolo

> Thanks!
>
> P.S. the guest_memfd mmap() series needs one minor fixup in patch 23[2]:
>
> diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
> index b86bf89a71e0..b3ca6737f304 100644
> --- a/tools/testing/selftests/kvm/guest_memfd_test.c
> +++ b/tools/testing/selftests/kvm/guest_memfd_test.c
> @@ -372,7 +372,7 @@ int main(int argc, char *argv[])
>          */
>         vm_types = kvm_check_cap(KVM_CAP_VM_TYPES);
>         if (!vm_types)
> -               vm_types = VM_TYPE_DEFAULT;
> +               vm_types = BIT(VM_TYPE_DEFAULT);
>
>         for_each_set_bit(vm_type, &vm_types, BITS_PER_TYPE(vm_types))
>                 test_guest_memfd(vm_type);
>
> [1] https://lore.kernel.org/all/20250729225455.670324-1-seanjc@google.com
> [2] https://lore.kernel.org/all/aIoWosN3UiPe2qQK@google.com
>
>
> The following changes since commit 8f5ae30d69d7543eee0d70083daf4de8fe15d585:
>
>   Linux 6.17-rc1 (2025-08-10 19:41:16 +0300)
>
> are available in the Git repository at:
>
>   https://github.com/kvm-x86/linux.git tags/kvm-x86-fixes-6.17-rc7
>
> for you to fetch changes up to dce1b33ed7430c7189b8cc1567498f9e6bf12731:
>
>   selftests: harness: Rename is_signed_type() to avoid collision with overflow.h (2025-08-20 08:04:09 -0700)
>
> ----------------------------------------------------------------
> KVM x86 fixes and a selftest fix for 6.17-rcN
>
>  - Use array_index_nospec() to sanitize the target vCPU ID when handling PV
>    IPIs and yields as the ID is guest-controlled.
>
>  - Drop a superfluous cpumask_empty() check when reclaiming SEV memory, as
>    the common case, by far, is that at least one CPU will have entered the
>    VM, and wbnoinvd_on_cpus_mask() will naturally handle the rare case where
>    the set of have_run_cpus is empty.
>
>  - Rename the is_signed_type() macro in kselftest_harness.h to is_signed_var()
>    to fix a collision with linux/overflow.h.  The collision generates compiler
>    warnings due to the two macros having different implementations.
>
> ----------------------------------------------------------------
> Sean Christopherson (1):
>       selftests: harness: Rename is_signed_type() to avoid collision with overflow.h
>
> Thijs Raymakers (1):
>       KVM: x86: use array_index_nospec with indices that come from guest
>
> Yury Norov (1):
>       KVM: SEV: don't check have_run_cpus in sev_writeback_caches()
>
>  arch/x86/kvm/lapic.c                        |  2 ++
>  arch/x86/kvm/svm/sev.c                      | 10 +++-------
>  arch/x86/kvm/x86.c                          |  7 +++++--
>  tools/testing/selftests/kselftest_harness.h |  4 ++--
>  4 files changed, 12 insertions(+), 11 deletions(-)
>