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| author |   Brijesh Singh <brijesh.singh@amd.com> | 2017-08-25 15:55:40 -0500 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2017-08-26 09:23:00 +0200 |
| commit | ea2800ddb20d6e66042051a61f66e6bea4fa0db7 (patch) | |
| tree | 8634800519b50832e143d26d3058122db858ece2 /arch/x86/kvm/mmu.c | |
| parent | Merge branch 'linus' into x86/mm to pick up fixes and to fix conflicts (diff) | |
| download | linux-dev-ea2800ddb20d6e66042051a61f66e6bea4fa0db7.tar.xz linux-dev-ea2800ddb20d6e66042051a61f66e6bea4fa0db7.zip | |
kvm/x86: Avoid clearing the C-bit in rsvd_bits()
The following commit:
d0ec49d4de90 ("kvm/x86/svm: Support Secure Memory Encryption within KVM")
uses __sme_clr() to remove the C-bit in rsvd_bits(). rsvd_bits() is
just a simple function to return some 1 bits. Applying a mask based
on properties of the host MMU is incorrect. Additionally, the masks
computed by __reset_rsvds_bits_mask also apply to guest page tables,
where the C bit is reserved since we don't emulate SME.
The fix is to clear the C-bit from rsvd_bits_mask array after it has been
populated from __reset_rsvds_bits_mask()
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: kvm@vger.kernel.org
Cc: paolo.bonzini@gmail.com
Fixes: d0ec49d ("kvm/x86/svm: Support Secure Memory Encryption within KVM")
Link: http://lkml.kernel.org/r/20170825205540.123531-1-brijesh.singh@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kvm/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 30 |
1 files changed, 27 insertions, 3 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index ccb70b8d16cc..04d750813c9d 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4109,16 +4109,28 @@ void reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context) { bool uses_nx = context->nx || context->base_role.smep_andnot_wp; + struct rsvd_bits_validate *shadow_zero_check; + int i; /* * Passing "true" to the last argument is okay; it adds a check * on bit 8 of the SPTEs which KVM doesn't use anyway. */ - __reset_rsvds_bits_mask(vcpu, &context->shadow_zero_check, + shadow_zero_check = &context->shadow_zero_check; + __reset_rsvds_bits_mask(vcpu, shadow_zero_check, boot_cpu_data.x86_phys_bits, context->shadow_root_level, uses_nx, guest_cpuid_has_gbpages(vcpu), is_pse(vcpu), true); + + if (!shadow_me_mask) + return; + + for (i = context->shadow_root_level; --i >= 0;) { + shadow_zero_check->rsvd_bits_mask[0][i] &= ~shadow_me_mask; + shadow_zero_check->rsvd_bits_mask[1][i] &= ~shadow_me_mask; + } + } EXPORT_SYMBOL_GPL(reset_shadow_zero_bits_mask); @@ -4136,17 +4148,29 @@ static void reset_tdp_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context) { + struct rsvd_bits_validate *shadow_zero_check; + int i; + + shadow_zero_check = &context->shadow_zero_check; + if (boot_cpu_is_amd()) - __reset_rsvds_bits_mask(vcpu, &context->shadow_zero_check, + __reset_rsvds_bits_mask(vcpu, shadow_zero_check, boot_cpu_data.x86_phys_bits, context->shadow_root_level, false, boot_cpu_has(X86_FEATURE_GBPAGES), true, true); else - __reset_rsvds_bits_mask_ept(&context->shadow_zero_check, + __reset_rsvds_bits_mask_ept(shadow_zero_check, boot_cpu_data.x86_phys_bits, false); + if (!shadow_me_mask) + return; + + for (i = context->shadow_root_level; --i >= 0;) { + shadow_zero_check->rsvd_bits_mask[0][i] &= ~shadow_me_mask; + shadow_zero_check->rsvd_bits_mask[1][i] &= ~shadow_me_mask; + } } /* |