From 81dd35d42c9aef3c1f7ae6ce4cf6a0d382661db5 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Tue, 7 Dec 2010 17:15:06 +0100 Subject: [PATCH] KVM: SVM: Add xsetbv intercept This patch implements the xsetbv intercept to the AMD part of KVM. This makes AVX usable in a save way for the guest on AVX capable AMD hardware. The patch is tested by using AVX in the guest and host in parallel and checking for data corruption. I also used the KVM xsave unit-tests and they all pass. Signed-off-by: Joerg Roedel Signed-off-by: Avi Kivity --- arch/x86/include/asm/svm.h | 2 ++ arch/x86/kvm/svm.c | 20 ++++++++++++++++---- 2 files changed, 18 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h index 82ecaa32fcf7..f7087bf9caf0 100644 --- a/arch/x86/include/asm/svm.h +++ b/arch/x86/include/asm/svm.h @@ -47,6 +47,7 @@ enum { INTERCEPT_MONITOR, INTERCEPT_MWAIT, INTERCEPT_MWAIT_COND, + INTERCEPT_XSETBV, }; @@ -329,6 +330,7 @@ struct __attribute__ ((__packed__)) vmcb { #define SVM_EXIT_MONITOR 0x08a #define SVM_EXIT_MWAIT 0x08b #define SVM_EXIT_MWAIT_COND 0x08c +#define SVM_EXIT_XSETBV 0x08d #define SVM_EXIT_NPF 0x400 #define SVM_EXIT_ERR -1 diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 4dbc37204de1..73461b1cfb05 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -935,6 +935,7 @@ static void init_vmcb(struct vcpu_svm *svm) set_intercept(svm, INTERCEPT_WBINVD); set_intercept(svm, INTERCEPT_MONITOR); set_intercept(svm, INTERCEPT_MWAIT); + set_intercept(svm, INTERCEPT_XSETBV); control->iopm_base_pa = iopm_base; control->msrpm_base_pa = __pa(svm->msrpm); @@ -2546,6 +2547,19 @@ static int skinit_interception(struct vcpu_svm *svm) return 1; } +static int xsetbv_interception(struct vcpu_svm *svm) +{ + u64 new_bv = kvm_read_edx_eax(&svm->vcpu); + u32 index = kvm_register_read(&svm->vcpu, VCPU_REGS_RCX); + + if (kvm_set_xcr(&svm->vcpu, index, new_bv) == 0) { + svm->next_rip = kvm_rip_read(&svm->vcpu) + 3; + skip_emulated_instruction(&svm->vcpu); + } + + return 1; +} + static int invalid_op_interception(struct vcpu_svm *svm) { kvm_queue_exception(&svm->vcpu, UD_VECTOR); @@ -2971,6 +2985,7 @@ static int (*svm_exit_handlers[])(struct vcpu_svm *svm) = { [SVM_EXIT_WBINVD] = emulate_on_interception, [SVM_EXIT_MONITOR] = invalid_op_interception, [SVM_EXIT_MWAIT] = invalid_op_interception, + [SVM_EXIT_XSETBV] = xsetbv_interception, [SVM_EXIT_NPF] = pf_interception, }; @@ -3624,10 +3639,6 @@ static void svm_cpuid_update(struct kvm_vcpu *vcpu) static void svm_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry) { switch (func) { - case 0x00000001: - /* Mask out xsave bit as long as it is not supported by SVM */ - entry->ecx &= ~(bit(X86_FEATURE_XSAVE)); - break; case 0x80000001: if (nested) entry->ecx |= (1 << 2); /* Set SVM bit */ @@ -3701,6 +3712,7 @@ static const struct trace_print_flags svm_exit_reasons_str[] = { { SVM_EXIT_WBINVD, "wbinvd" }, { SVM_EXIT_MONITOR, "monitor" }, { SVM_EXIT_MWAIT, "mwait" }, + { SVM_EXIT_XSETBV, "xsetbv" }, { SVM_EXIT_NPF, "npf" }, { -1, NULL } }; -- 2.39.5