| Message ID | 45a2dbcbf694c48f1fb6a834a0f97a36a226a172.1646655860.git.houwenlong.hwl@antgroup.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,1/2] KVM: x86: Only do MSR filtering when access MSR by rdmsr/wrmsr | expand |
On 3/7/22 13:26, Hou Wenlong wrote: > When RDTSCP is supported but RDPID is not supported in host, > RDPID emulation is available. However, __kvm_get_msr() would > only fail when RDTSCP/RDPID both are disabled in guest, so > the emulator wouldn't inject a #UD when RDPID is disabled but > RDTSCP is enabled in guest. > > Fixes: fb6d4d340e05 ("KVM: x86: emulate RDPID") > Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com> > --- > arch/x86/kvm/emulate.c | 4 +++- > arch/x86/kvm/kvm_emulate.h | 1 + > arch/x86/kvm/x86.c | 6 ++++++ > 3 files changed, 10 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > index 3497a35bd085..be83c9c8482d 100644 > --- a/arch/x86/kvm/emulate.c > +++ b/arch/x86/kvm/emulate.c > @@ -3521,8 +3521,10 @@ static int em_rdpid(struct x86_emulate_ctxt *ctxt) > { > u64 tsc_aux = 0; > > - if (ctxt->ops->get_msr(ctxt, MSR_TSC_AUX, &tsc_aux)) > + if (!ctxt->ops->guest_has_rdpid(ctxt)) > return emulate_ud(ctxt); > + > + ctxt->ops->get_msr(ctxt, MSR_TSC_AUX, &tsc_aux); > ctxt->dst.val = tsc_aux; > return X86EMUL_CONTINUE; > } > diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h > index 29ac5a9679e5..1cbd46cf71f9 100644 > --- a/arch/x86/kvm/kvm_emulate.h > +++ b/arch/x86/kvm/kvm_emulate.h > @@ -228,6 +228,7 @@ struct x86_emulate_ops { > 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); > + bool (*guest_has_rdpid)(struct x86_emulate_ctxt *ctxt); > > void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked); > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 09c5677f4186..44f97038d3e5 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -7723,6 +7723,11 @@ static bool emulator_guest_has_fxsr(struct x86_emulate_ctxt *ctxt) > return guest_cpuid_has(emul_to_vcpu(ctxt), X86_FEATURE_FXSR); > } > > +static bool emulator_guest_has_rdpid(struct x86_emulate_ctxt *ctxt) > +{ > + return guest_cpuid_has(emul_to_vcpu(ctxt), X86_FEATURE_RDPID); > +} > + > static ulong emulator_read_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg) > { > return kvm_register_read_raw(emul_to_vcpu(ctxt), reg); > @@ -7807,6 +7812,7 @@ static const struct x86_emulate_ops emulate_ops = { > .guest_has_long_mode = emulator_guest_has_long_mode, > .guest_has_movbe = emulator_guest_has_movbe, > .guest_has_fxsr = emulator_guest_has_fxsr, > + .guest_has_rdpid = emulator_guest_has_rdpid, > .set_nmi_mask = emulator_set_nmi_mask, > .get_hflags = emulator_get_hflags, > .exiting_smm = emulator_exiting_smm, Queued, thanks. Would you try replacing the ->guest_has_... callbacks with just one that takes an X86_FEATURE_* constant as a second argument? Paolo
On Wed, Mar 16, 2022 at 06:18:11AM +0800, Paolo Bonzini wrote: > On 3/7/22 13:26, Hou Wenlong wrote: > >When RDTSCP is supported but RDPID is not supported in host, > >RDPID emulation is available. However, __kvm_get_msr() would > >only fail when RDTSCP/RDPID both are disabled in guest, so > >the emulator wouldn't inject a #UD when RDPID is disabled but > >RDTSCP is enabled in guest. > > > >Fixes: fb6d4d340e05 ("KVM: x86: emulate RDPID") > >Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com> > >--- > > arch/x86/kvm/emulate.c | 4 +++- > > arch/x86/kvm/kvm_emulate.h | 1 + > > arch/x86/kvm/x86.c | 6 ++++++ > > 3 files changed, 10 insertions(+), 1 deletion(-) > > > >diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > >index 3497a35bd085..be83c9c8482d 100644 > >--- a/arch/x86/kvm/emulate.c > >+++ b/arch/x86/kvm/emulate.c > >@@ -3521,8 +3521,10 @@ static int em_rdpid(struct x86_emulate_ctxt *ctxt) > > { > > u64 tsc_aux = 0; > >- if (ctxt->ops->get_msr(ctxt, MSR_TSC_AUX, &tsc_aux)) > >+ if (!ctxt->ops->guest_has_rdpid(ctxt)) > > return emulate_ud(ctxt); > >+ > >+ ctxt->ops->get_msr(ctxt, MSR_TSC_AUX, &tsc_aux); > > ctxt->dst.val = tsc_aux; > > return X86EMUL_CONTINUE; > > } > >diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h > >index 29ac5a9679e5..1cbd46cf71f9 100644 > >--- a/arch/x86/kvm/kvm_emulate.h > >+++ b/arch/x86/kvm/kvm_emulate.h > >@@ -228,6 +228,7 @@ struct x86_emulate_ops { > > 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); > >+ bool (*guest_has_rdpid)(struct x86_emulate_ctxt *ctxt); > > void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked); > >diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > >index 09c5677f4186..44f97038d3e5 100644 > >--- a/arch/x86/kvm/x86.c > >+++ b/arch/x86/kvm/x86.c > >@@ -7723,6 +7723,11 @@ static bool emulator_guest_has_fxsr(struct x86_emulate_ctxt *ctxt) > > return guest_cpuid_has(emul_to_vcpu(ctxt), X86_FEATURE_FXSR); > > } > >+static bool emulator_guest_has_rdpid(struct x86_emulate_ctxt *ctxt) > >+{ > >+ return guest_cpuid_has(emul_to_vcpu(ctxt), X86_FEATURE_RDPID); > >+} > >+ > > static ulong emulator_read_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg) > > { > > return kvm_register_read_raw(emul_to_vcpu(ctxt), reg); > >@@ -7807,6 +7812,7 @@ static const struct x86_emulate_ops emulate_ops = { > > .guest_has_long_mode = emulator_guest_has_long_mode, > > .guest_has_movbe = emulator_guest_has_movbe, > > .guest_has_fxsr = emulator_guest_has_fxsr, > >+ .guest_has_rdpid = emulator_guest_has_rdpid, > > .set_nmi_mask = emulator_set_nmi_mask, > > .get_hflags = emulator_get_hflags, > > .exiting_smm = emulator_exiting_smm, > > Queued, thanks. > > Would you try replacing the ->guest_has_... callbacks with just one > that takes an X86_FEATURE_* constant as a second argument? > > Paolo I've tried doing it before sending the patch, but the compilation failed due to BUILD_BUG_ON in reverse_cpuid_check(), which requires a constant.
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 3497a35bd085..be83c9c8482d 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3521,8 +3521,10 @@ static int em_rdpid(struct x86_emulate_ctxt *ctxt) { u64 tsc_aux = 0; - if (ctxt->ops->get_msr(ctxt, MSR_TSC_AUX, &tsc_aux)) + if (!ctxt->ops->guest_has_rdpid(ctxt)) return emulate_ud(ctxt); + + ctxt->ops->get_msr(ctxt, MSR_TSC_AUX, &tsc_aux); ctxt->dst.val = tsc_aux; return X86EMUL_CONTINUE; } diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index 29ac5a9679e5..1cbd46cf71f9 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -228,6 +228,7 @@ struct x86_emulate_ops { 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); + bool (*guest_has_rdpid)(struct x86_emulate_ctxt *ctxt); void (*set_nmi_mask)(struct x86_emulate_ctxt *ctxt, bool masked); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 09c5677f4186..44f97038d3e5 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7723,6 +7723,11 @@ static bool emulator_guest_has_fxsr(struct x86_emulate_ctxt *ctxt) return guest_cpuid_has(emul_to_vcpu(ctxt), X86_FEATURE_FXSR); } +static bool emulator_guest_has_rdpid(struct x86_emulate_ctxt *ctxt) +{ + return guest_cpuid_has(emul_to_vcpu(ctxt), X86_FEATURE_RDPID); +} + static ulong emulator_read_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg) { return kvm_register_read_raw(emul_to_vcpu(ctxt), reg); @@ -7807,6 +7812,7 @@ static const struct x86_emulate_ops emulate_ops = { .guest_has_long_mode = emulator_guest_has_long_mode, .guest_has_movbe = emulator_guest_has_movbe, .guest_has_fxsr = emulator_guest_has_fxsr, + .guest_has_rdpid = emulator_guest_has_rdpid, .set_nmi_mask = emulator_set_nmi_mask, .get_hflags = emulator_get_hflags, .exiting_smm = emulator_exiting_smm,
When RDTSCP is supported but RDPID is not supported in host, RDPID emulation is available. However, __kvm_get_msr() would only fail when RDTSCP/RDPID both are disabled in guest, so the emulator wouldn't inject a #UD when RDPID is disabled but RDTSCP is enabled in guest. Fixes: fb6d4d340e05 ("KVM: x86: emulate RDPID") Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com> --- arch/x86/kvm/emulate.c | 4 +++- arch/x86/kvm/kvm_emulate.h | 1 + arch/x86/kvm/x86.c | 6 ++++++ 3 files changed, 10 insertions(+), 1 deletion(-)