From a0c0feb57992c5caed170feab8a68c51306eb7c3 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 2 Sep 2014 13:24:12 +0200 Subject: KVM: x86: reserve bit 8 of non-leaf PDPEs and PML4Es in 64-bit mode on AMD Bit 8 would be the "global" bit, which does not quite make sense for non-leaf page table entries. Intel ignores it; AMD ignores it in PDEs, but reserves it in PDPEs and PML4Es. The SVM test is relying on this behavior, so enforce it. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/cpuid.h | 8 ++++++++ arch/x86/kvm/mmu.c | 13 +++++++++++-- 2 files changed, 19 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h index a538059..43b33e3 100644 --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -88,6 +88,14 @@ static inline bool guest_cpuid_has_x2apic(struct kvm_vcpu *vcpu) return best && (best->ecx & bit(X86_FEATURE_X2APIC)); } +static inline bool guest_cpuid_is_amd(struct kvm_vcpu *vcpu) +{ + struct kvm_cpuid_entry2 *best; + + best = kvm_find_cpuid_entry(vcpu, 0, 0); + return best && best->ebx == X86EMUL_CPUID_VENDOR_AuthenticAMD_ebx; +} + static inline bool guest_cpuid_has_gbpages(struct kvm_vcpu *vcpu) { struct kvm_cpuid_entry2 *best; diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 6b6df0c..5b93a59 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -3512,6 +3512,7 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu, int maxphyaddr = cpuid_maxphyaddr(vcpu); u64 exb_bit_rsvd = 0; u64 gbpages_bit_rsvd = 0; + u64 nonleaf_bit8_rsvd = 0; context->bad_mt_xwr = 0; @@ -3519,6 +3520,14 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu, exb_bit_rsvd = rsvd_bits(63, 63); if (!guest_cpuid_has_gbpages(vcpu)) gbpages_bit_rsvd = rsvd_bits(7, 7); + + /* + * Non-leaf PML4Es and PDPEs reserve bit 8 (which would be the G bit for + * leaf entries) on AMD CPUs only. + */ + if (guest_cpuid_is_amd(vcpu)) + nonleaf_bit8_rsvd = rsvd_bits(8, 8); + switch (context->root_level) { case PT32_ROOT_LEVEL: /* no rsvd bits for 2 level 4K page table entries */ @@ -3553,9 +3562,9 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu, break; case PT64_ROOT_LEVEL: context->rsvd_bits_mask[0][3] = exb_bit_rsvd | - rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 7); + nonleaf_bit8_rsvd | rsvd_bits(7, 7) | rsvd_bits(maxphyaddr, 51); context->rsvd_bits_mask[0][2] = exb_bit_rsvd | - gbpages_bit_rsvd | rsvd_bits(maxphyaddr, 51); + nonleaf_bit8_rsvd | gbpages_bit_rsvd | rsvd_bits(maxphyaddr, 51); context->rsvd_bits_mask[0][1] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 51); context->rsvd_bits_mask[0][0] = exb_bit_rsvd | -- cgit v1.1