From 191c8137a93989825f0e9f78a198367dde677216 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 18 Apr 2019 18:32:50 +0200 Subject: [PATCH] x86/kvm: Implement HWCR support MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The 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 Cc: Jim Mattson Cc: Joerg Roedel Cc: KVM Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Sean Christopherson Cc: Tom Lendacky Cc: Tony Luck Cc: Yazen Ghannam Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_host.h | 3 +++ arch/x86/kvm/x86.c | 34 +++++++++++++++++++++++++++++----- 2 files changed, 32 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 8d68ba0..2532bfb 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -781,6 +781,9 @@ 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 c095070..a7ea346 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1171,6 +1171,8 @@ static u32 emulated_msrs[] = { MSR_MISC_FEATURES_ENABLES, MSR_AMD64_VIRT_SPEC_CTRL, MSR_IA32_POWER_CTL, + + MSR_K7_HWCR, }; static unsigned num_emulated_msrs; @@ -2294,6 +2296,18 @@ 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 can_set_mci_status(struct kvm_vcpu *vcpu) +{ + /* McStatusWrEn enabled? */ + if (guest_cpuid_is_amd(vcpu)) + return !!(vcpu->arch.msr_hwcr & BIT_ULL(18)); + + return false; +} + static int set_msr_mce(struct kvm_vcpu *vcpu, struct msr_data *msr_info) { u64 mcg_cap = vcpu->arch.mcg_cap; @@ -2325,9 +2339,14 @@ 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; + + /* MCi_STATUS */ if (!msr_info->host_initiated && - (offset & 0x3) == 1 && data != 0) - return -1; + (offset & 0x3) == 1 && data != 0) { + if (!can_set_mci_status(vcpu)) + return -1; + } + vcpu->arch.mce_banks[offset] = data; break; } @@ -2476,8 +2495,11 @@ 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; @@ -2751,7 +2773,6 @@ 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: @@ -2915,6 +2936,9 @@ 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); -- 2.7.4