From 5ae78e95ed0c771935d0d24291d221312524830c Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 17 Dec 2019 13:32:38 -0800 Subject: [PATCH] KVM: x86: Add dedicated emulator helpers for querying CPUID features Add feature-specific helpers for querying guest CPUID support from the emulator instead of having the emulator do a full CPUID and perform its own bit tests. The primary motivation is to eliminate the emulator's usage of bit() so that future patches can add more extensive build-time assertions on the usage of bit() without having to expose yet more code to the emulator. Note, providing a generic guest_cpuid_has() to the emulator doesn't work due to the existing built-time assertions in guest_cpuid_has(), which require the feature being checked to be a compile-time constant. No functional change intended. Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_emulate.h | 4 ++++ arch/x86/kvm/emulate.c | 21 +++------------------ arch/x86/kvm/x86.c | 18 ++++++++++++++++++ 3 files changed, 25 insertions(+), 18 deletions(-) diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index 77cf6c11f66b..03946eb3e2b9 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -222,6 +222,10 @@ struct x86_emulate_ops { bool (*get_cpuid)(struct x86_emulate_ctxt *ctxt, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx, bool check_limit); + bool (*guest_has_long_mode)(struct x86_emulate_ctxt *ctxt); + bool (*guest_has_movbe)(struct x86_emulate_ctxt *ctxt); + bool (*guest_has_fxsr)(struct x86_emulate_ctxt *ctxt); + void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked); unsigned (*get_hflags)(struct x86_emulate_ctxt *ctxt); diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 952d1a4f4d7e..e9833e345a5c 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2348,12 +2348,7 @@ static int em_lseg(struct x86_emulate_ctxt *ctxt) static int emulator_has_longmode(struct x86_emulate_ctxt *ctxt) { #ifdef CONFIG_X86_64 - u32 eax, ebx, ecx, edx; - - eax = 0x80000001; - ecx = 0; - ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, false); - return edx & bit(X86_FEATURE_LM); + return ctxt->ops->guest_has_long_mode(ctxt); #else return false; #endif @@ -3618,18 +3613,11 @@ static int em_mov(struct x86_emulate_ctxt *ctxt) return X86EMUL_CONTINUE; } -#define FFL(x) bit(X86_FEATURE_##x) - static int em_movbe(struct x86_emulate_ctxt *ctxt) { - u32 ebx, ecx, edx, eax = 1; u16 tmp; - /* - * Check MOVBE is set in the guest-visible CPUID leaf. - */ - ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, false); - if (!(ecx & FFL(MOVBE))) + if (!ctxt->ops->guest_has_movbe(ctxt)) return emulate_ud(ctxt); switch (ctxt->op_bytes) { @@ -4027,10 +4015,7 @@ static int em_movsxd(struct x86_emulate_ctxt *ctxt) static int check_fxsr(struct x86_emulate_ctxt *ctxt) { - u32 eax = 1, ebx, ecx = 0, edx; - - ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, false); - if (!(edx & FFL(FXSR))) + if (!ctxt->ops->guest_has_fxsr(ctxt)) return emulate_ud(ctxt); if (ctxt->ops->get_cr(ctxt, 0) & (X86_CR0_TS | X86_CR0_EM)) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 456fc131c95e..60b0d69af0f1 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6245,6 +6245,21 @@ static bool emulator_get_cpuid(struct x86_emulate_ctxt *ctxt, return kvm_cpuid(emul_to_vcpu(ctxt), eax, ebx, ecx, edx, check_limit); } +static bool emulator_guest_has_long_mode(struct x86_emulate_ctxt *ctxt) +{ + return guest_cpuid_has(emul_to_vcpu(ctxt), X86_FEATURE_LM); +} + +static bool emulator_guest_has_movbe(struct x86_emulate_ctxt *ctxt) +{ + return guest_cpuid_has(emul_to_vcpu(ctxt), X86_FEATURE_MOVBE); +} + +static bool emulator_guest_has_fxsr(struct x86_emulate_ctxt *ctxt) +{ + return guest_cpuid_has(emul_to_vcpu(ctxt), X86_FEATURE_FXSR); +} + static ulong emulator_read_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg) { return kvm_register_read(emul_to_vcpu(ctxt), reg); @@ -6322,6 +6337,9 @@ static const struct x86_emulate_ops emulate_ops = { .fix_hypercall = emulator_fix_hypercall, .intercept = emulator_intercept, .get_cpuid = emulator_get_cpuid, + .guest_has_long_mode = emulator_guest_has_long_mode, + .guest_has_movbe = emulator_guest_has_movbe, + .guest_has_fxsr = emulator_guest_has_fxsr, .set_nmi_mask = emulator_set_nmi_mask, .get_hflags = emulator_get_hflags, .set_hflags = emulator_set_hflags, -- 2.11.0