On Wed, Oct 6, 2021 at 1:39 PM Michael Roth <michael.roth@xxxxxxx> wrote:
>
> Recent kernels have checks to ensure the GPA values in special-purpose
> registers like CR3 are within the maximum physical address range and
> don't overlap with anything in the upper/reserved range. In the case of
> SEV kselftest guests booting directly into 64-bit mode, CR3 needs to be
> initialized to the GPA of the page table root, with the encryption bit
> set. The kernel accounts for this encryption bit by removing it from
> reserved bit range when the guest advertises the bit position via
> KVM_SET_CPUID*, but kselftests currently call KVM_SET_SREGS as part of
> vm_vcpu_add_default(), *prior* to vCPU creation, so there's no
> opportunity to call KVM_SET_CPUID* in advance. As a result,
> KVM_SET_SREGS will return an error in these cases.
>
> Address this by moving vcpu_set_cpuid() (which calls KVM_SET_CPUID*)
> ahead of vcpu_setup() (which calls KVM_SET_SREGS).
>
> While there, address a typo in the assertion that triggers when
> KVM_SET_SREGS fails.
>
> Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
> ---
> tools/testing/selftests/kvm/lib/kvm_util.c | 2 +-
> tools/testing/selftests/kvm/lib/x86_64/processor.c | 4 +---
> 2 files changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index ef88fdc7e46b..646cffd86d09 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -1906,7 +1906,7 @@ void vcpu_sregs_get(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_sregs *sregs)
> void vcpu_sregs_set(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_sregs *sregs)
> {
> int ret = _vcpu_sregs_set(vm, vcpuid, sregs);
> - TEST_ASSERT(ret == 0, "KVM_RUN IOCTL failed, "
> + TEST_ASSERT(ret == 0, "KVM_SET_SREGS IOCTL failed, "
> "rc: %i errno: %i", ret, errno);
> }
>
> diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> index 0bbd88fe1127..1ab4c20f5d12 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> @@ -660,6 +660,7 @@ void vm_vcpu_add_default(struct kvm_vm *vm, uint32_t vcpuid, void *guest_code)
>
> /* Create VCPU */
> vm_vcpu_add(vm, vcpuid);
> + vcpu_set_cpuid(vm, vcpuid, kvm_get_supported_cpuid());
> vcpu_setup(vm, vcpuid);
>
> /* Setup guest general purpose registers */
> @@ -672,9 +673,6 @@ void vm_vcpu_add_default(struct kvm_vm *vm, uint32_t vcpuid, void *guest_code)
> /* Setup the MP state */
> mp_state.mp_state = 0;
> vcpu_set_mp_state(vm, vcpuid, &mp_state);
> -
> - /* Setup supported CPUIDs */
> - vcpu_set_cpuid(vm, vcpuid, kvm_get_supported_cpuid());
> }
>
> /*
> --
> 2.25.1
>
Good catch.
Reviewed-by: Nathan Tempelman <natet@xxxxxxxxxx>
