From a807b78ad04b2eaa348f52f5cc7702385b6de1ee Mon Sep 17 00:00:00 2001 From: Emanuele Giuseppe Esposito Date: Wed, 1 Feb 2023 08:29:03 -0500 Subject: [PATCH] kvm: vmx: Add IA32_FLUSH_CMD guest support Expose IA32_FLUSH_CMD to the guest if the guest CPUID enumerates support for this MSR. As with IA32_PRED_CMD, permission for unintercepted writes to this MSR will be granted to the guest after the first non-zero write. Co-developed-by: Jim Mattson Signed-off-by: Jim Mattson Signed-off-by: Emanuele Giuseppe Esposito Message-Id: <20230201132905.549148-2-eesposit@redhat.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 3 ++ arch/x86/kvm/vmx/vmx.c | 68 +++++++++++++++++++++++++-------------- 2 files changed, 46 insertions(+), 25 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 1bc2b80273c9..f63b28f46a71 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -654,6 +654,9 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu, nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0, MSR_IA32_PRED_CMD, MSR_TYPE_W); + nested_vmx_set_intercept_for_msr(vmx, msr_bitmap_l1, msr_bitmap_l0, + MSR_IA32_FLUSH_CMD, MSR_TYPE_W); + kvm_vcpu_unmap(vcpu, &vmx->nested.msr_bitmap_map, false); vmx->nested.force_msr_bitmap_recalc = false; diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index f777509ecf17..d7bf14abdba1 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2133,6 +2133,39 @@ static u64 vmx_get_supported_debugctl(struct kvm_vcpu *vcpu, bool host_initiated return debugctl; } +static int vmx_set_msr_ia32_cmd(struct kvm_vcpu *vcpu, + struct msr_data *msr_info, + bool guest_has_feat, u64 cmd, + int x86_feature_bit) +{ + if (!msr_info->host_initiated && !guest_has_feat) + return 1; + + if (!(msr_info->data & ~cmd)) + return 1; + if (!boot_cpu_has(x86_feature_bit)) + return 1; + if (!msr_info->data) + return 0; + + wrmsrl(msr_info->index, cmd); + + /* + * For non-nested: + * When it's written (to non-zero) for the first time, pass + * it through. + * + * For nested: + * The handling of the MSR bitmap for L2 guests is done in + * nested_vmx_prepare_msr_bitmap. We should not touch the + * vmcs02.msr_bitmap here since it gets completely overwritten + * in the merging. + */ + vmx_disable_intercept_for_msr(vcpu, msr_info->index, MSR_TYPE_W); + + return 0; +} + /* * Writes msr value into the appropriate "register". * Returns 0 on success, non-0 otherwise. @@ -2286,31 +2319,16 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) return 1; goto find_uret_msr; case MSR_IA32_PRED_CMD: - if (!msr_info->host_initiated && - !guest_has_pred_cmd_msr(vcpu)) - return 1; - - if (data & ~PRED_CMD_IBPB) - return 1; - if (!boot_cpu_has(X86_FEATURE_IBPB)) - return 1; - if (!data) - break; - - wrmsrl(MSR_IA32_PRED_CMD, PRED_CMD_IBPB); - - /* - * For non-nested: - * When it's written (to non-zero) for the first time, pass - * it through. - * - * For nested: - * The handling of the MSR bitmap for L2 guests is done in - * nested_vmx_prepare_msr_bitmap. We should not touch the - * vmcs02.msr_bitmap here since it gets completely overwritten - * in the merging. - */ - vmx_disable_intercept_for_msr(vcpu, MSR_IA32_PRED_CMD, MSR_TYPE_W); + ret = vmx_set_msr_ia32_cmd(vcpu, msr_info, + guest_has_pred_cmd_msr(vcpu), + PRED_CMD_IBPB, + X86_FEATURE_IBPB); + break; + case MSR_IA32_FLUSH_CMD: + ret = vmx_set_msr_ia32_cmd(vcpu, msr_info, + guest_cpuid_has(vcpu, X86_FEATURE_FLUSH_L1D), + L1D_FLUSH, + X86_FEATURE_FLUSH_L1D); break; case MSR_IA32_CR_PAT: if (!kvm_pat_valid(data)) -- 2.20.1