Hi all, here's v5 which keeps the HWCR functionality in kvm/x86.c so that emulation of AMD guests on Intel hw still can work. -- From: Borislav Petkov <bp@xxxxxxx> The AMD hardware configuration register has some useful bits which can be used by guests. Implement McStatusWrEn which can be used by guests when injecting MCEs with the in-kernel mce-inject module. For that, we need to set bit 18 - McStatusWrEn - first, before writing the MCi_STATUS registers (otherwise we #GP). Add the required machinery to do so. Signed-off-by: Borislav Petkov <bp@xxxxxxx> Cc: Jim Mattson <jmattson@xxxxxxxxxx> Cc: Joerg Roedel <joro@xxxxxxxxxx> Cc: KVM <kvm@xxxxxxxxxxxxxxx> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx> Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx> Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> Cc: Tom Lendacky <thomas.lendacky@xxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Cc: Yazen Ghannam <Yazen.Ghannam@xxxxxxx> --- arch/x86/include/asm/kvm_host.h | 3 +++ arch/x86/kvm/x86.c | 45 ++++++++++++++++++++++++++++----- 2 files changed, 42 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 159b5988292f..541c431df806 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -780,6 +780,9 @@ struct kvm_vcpu_arch { /* Flush the L1 Data cache for L1TF mitigation on VMENTER */ bool l1tf_flush_l1d; + + /* AMD MSRC001_0015 Hardware Configuration */ + u64 msr_hwcr; }; struct kvm_lpage_info { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 099b851dabaf..e07f21c1d2d4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2273,6 +2273,30 @@ static void kvmclock_sync_fn(struct work_struct *work) KVMCLOCK_SYNC_PERIOD); } +/* + * On AMD, HWCR[McStatusWrEn] controls whether setting MCi_STATUS results in #GP. + */ +static bool __set_mci_status(struct kvm_vcpu *vcpu, struct msr_data *msr_info) +{ + if (guest_cpuid_is_amd(vcpu)) { + struct msr_data tmp; + + tmp.index = MSR_K7_HWCR; + + if (kvm_get_msr_common(vcpu, &tmp)) + return false; + + /* McStatusWrEn enabled? */ + if (tmp.data & BIT_ULL(18)) + return true; + } + + if (msr_info->data != 0) + return false; + + return true; +} + static int set_msr_mce(struct kvm_vcpu *vcpu, struct msr_data *msr_info) { u64 mcg_cap = vcpu->arch.mcg_cap; @@ -2304,9 +2328,13 @@ static int set_msr_mce(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if ((offset & 0x3) == 0 && data != 0 && (data | (1 << 10)) != ~(u64)0) return -1; - if (!msr_info->host_initiated && - (offset & 0x3) == 1 && data != 0) - return -1; + + /* MCi_STATUS */ + if ((offset & 0x3) == 1 && !msr_info->host_initiated) { + if (!__set_mci_status(vcpu, msr_info)) + return -1; + } + vcpu->arch.mce_banks[offset] = data; break; } @@ -2455,8 +2483,11 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) data &= ~(u64)0x40; /* ignore flush filter disable */ data &= ~(u64)0x100; /* ignore ignne emulation enable */ data &= ~(u64)0x8; /* ignore TLB cache disable */ - data &= ~(u64)0x40000; /* ignore Mc status write enable */ - if (data != 0) { + + /* Handle McStatusWrEn */ + if (data == BIT_ULL(18)) { + vcpu->arch.msr_hwcr = data; + } else if (data != 0) { vcpu_unimpl(vcpu, "unimplemented HWCR wrmsr: 0x%llx\n", data); return 1; @@ -2730,7 +2761,6 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) case MSR_K8_SYSCFG: case MSR_K8_TSEG_ADDR: case MSR_K8_TSEG_MASK: - case MSR_K7_HWCR: case MSR_VM_HSAVE_PA: case MSR_K8_INT_PENDING_MSG: case MSR_AMD64_NB_CFG: @@ -2894,6 +2924,9 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) case MSR_MISC_FEATURES_ENABLES: msr_info->data = vcpu->arch.msr_misc_features_enables; break; + case MSR_K7_HWCR: + msr_info->data = vcpu->arch.msr_hwcr; + break; default: if (kvm_pmu_is_valid_msr(vcpu, msr_info->index)) return kvm_pmu_get_msr(vcpu, msr_info->index, &msr_info->data); -- 2.21.0 -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.