| Message ID | 20250124132048.3229049-49-xiaoyao.li@intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | QEMU TDX support | expand |
Xiaoyao Li <xiaoyao.li@intel.com> writes: > Use KVM_TDX_GET_CPUID to get the CPUIDs that are managed and enfored > by TDX module for TD guest. Check QEMU's configuration against the > fetched data. > > Print wanring message when 1. a feature is not supported but requested > by QEMU or 2. QEMU doesn't want to expose a feature while it is enforced > enabled. > > - If cpu->enforced_cpuid is not set, prints the warning message of both > 1) and 2) and tweak QEMU's configuration. > > - If cpu->enforced_cpuid is set, quit if any case of 1) or 2). > > Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> > --- > target/i386/cpu.c | 33 ++++++++++++++- > target/i386/cpu.h | 7 +++ > target/i386/kvm/tdx.c | 99 +++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 137 insertions(+), 2 deletions(-) > > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index f1330627adbb..a948fd0bd674 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -5482,8 +5482,8 @@ static bool x86_cpu_have_filtered_features(X86CPU *cpu) > return false; > } > > -static void mark_unavailable_features(X86CPU *cpu, FeatureWord w, uint64_t mask, > - const char *verbose_prefix) > +void mark_unavailable_features(X86CPU *cpu, FeatureWord w, uint64_t mask, > + const char *verbose_prefix) > { > CPUX86State *env = &cpu->env; > FeatureWordInfo *f = &feature_word_info[w]; > @@ -5510,6 +5510,35 @@ static void mark_unavailable_features(X86CPU *cpu, FeatureWord w, uint64_t mask, > } > } > > +void mark_forced_on_features(X86CPU *cpu, FeatureWord w, uint64_t mask, > + const char *verbose_prefix) > +{ > + CPUX86State *env = &cpu->env; > + FeatureWordInfo *f = &feature_word_info[w]; > + int i; > + > + if (!cpu->force_features) { > + env->features[w] |= mask; > + } > + > + cpu->forced_on_features[w] |= mask; > + > + if (!verbose_prefix) { > + return; > + } > + > + for (i = 0; i < 64; ++i) { > + if ((1ULL << i) & mask) { > + g_autofree char *feat_word_str = feature_word_description(f); Does not compile for me: ../target/i386/cpu.c: In function ‘mark_forced_on_features’: ../target/i386/cpu.c:5531:46: error: too few arguments to function ‘feature_word_description’ 5531 | g_autofree char *feat_word_str = feature_word_description(f); | ^~~~~~~~~~~~~~~~~~~~~~~~ ../target/i386/cpu.c:5451:14: note: declared here 5451 | static char *feature_word_description(FeatureWordInfo *f, uint32_t bit) | ^~~~~~~~~~~~~~~~~~~~~~~~ > + warn_report("%s: %s%s%s [bit %d]", > + verbose_prefix, > + feat_word_str, > + f->feat_names[i] ? "." : "", > + f->feat_names[i] ? f->feat_names[i] : "", i); > + } > + } > +} > + > static void x86_cpuid_version_get_family(Object *obj, Visitor *v, > const char *name, void *opaque, > Error **errp) [...]
On 2/5/2025 5:28 PM, Markus Armbruster wrote: > Xiaoyao Li <xiaoyao.li@intel.com> writes: > >> Use KVM_TDX_GET_CPUID to get the CPUIDs that are managed and enfored >> by TDX module for TD guest. Check QEMU's configuration against the >> fetched data. >> >> Print wanring message when 1. a feature is not supported but requested >> by QEMU or 2. QEMU doesn't want to expose a feature while it is enforced >> enabled. >> >> - If cpu->enforced_cpuid is not set, prints the warning message of both >> 1) and 2) and tweak QEMU's configuration. >> >> - If cpu->enforced_cpuid is set, quit if any case of 1) or 2). >> >> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> >> --- >> target/i386/cpu.c | 33 ++++++++++++++- >> target/i386/cpu.h | 7 +++ >> target/i386/kvm/tdx.c | 99 +++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 137 insertions(+), 2 deletions(-) >> >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c >> index f1330627adbb..a948fd0bd674 100644 >> --- a/target/i386/cpu.c >> +++ b/target/i386/cpu.c >> @@ -5482,8 +5482,8 @@ static bool x86_cpu_have_filtered_features(X86CPU *cpu) >> return false; >> } >> >> -static void mark_unavailable_features(X86CPU *cpu, FeatureWord w, uint64_t mask, >> - const char *verbose_prefix) >> +void mark_unavailable_features(X86CPU *cpu, FeatureWord w, uint64_t mask, >> + const char *verbose_prefix) >> { >> CPUX86State *env = &cpu->env; >> FeatureWordInfo *f = &feature_word_info[w]; >> @@ -5510,6 +5510,35 @@ static void mark_unavailable_features(X86CPU *cpu, FeatureWord w, uint64_t mask, >> } >> } >> >> +void mark_forced_on_features(X86CPU *cpu, FeatureWord w, uint64_t mask, >> + const char *verbose_prefix) >> +{ >> + CPUX86State *env = &cpu->env; >> + FeatureWordInfo *f = &feature_word_info[w]; >> + int i; >> + >> + if (!cpu->force_features) { >> + env->features[w] |= mask; >> + } >> + >> + cpu->forced_on_features[w] |= mask; >> + >> + if (!verbose_prefix) { >> + return; >> + } >> + >> + for (i = 0; i < 64; ++i) { >> + if ((1ULL << i) & mask) { >> + g_autofree char *feat_word_str = feature_word_description(f); > > Does not compile for me: > > ../target/i386/cpu.c: In function ‘mark_forced_on_features’: > ../target/i386/cpu.c:5531:46: error: too few arguments to function ‘feature_word_description’ > 5531 | g_autofree char *feat_word_str = feature_word_description(f); > | ^~~~~~~~~~~~~~~~~~~~~~~~ > ../target/i386/cpu.c:5451:14: note: declared here > 5451 | static char *feature_word_description(FeatureWordInfo *f, uint32_t bit) > | ^~~~~~~~~~~~~~~~~~~~~~~~ As mentioned in the cover letter, this series depends on a minor one: https://lore.kernel.org/qemu-devel/20241217123932.948789-1-xiaoyao.li@intel.com/ >> + warn_report("%s: %s%s%s [bit %d]", >> + verbose_prefix, >> + feat_word_str, >> + f->feat_names[i] ? "." : "", >> + f->feat_names[i] ? f->feat_names[i] : "", i); >> + } >> + } >> +} >> + >> static void x86_cpuid_version_get_family(Object *obj, Visitor *v, >> const char *name, void *opaque, >> Error **errp) > > [...] >
diff --git a/target/i386/cpu.c b/target/i386/cpu.c index f1330627adbb..a948fd0bd674 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -5482,8 +5482,8 @@ static bool x86_cpu_have_filtered_features(X86CPU *cpu) return false; } -static void mark_unavailable_features(X86CPU *cpu, FeatureWord w, uint64_t mask, - const char *verbose_prefix) +void mark_unavailable_features(X86CPU *cpu, FeatureWord w, uint64_t mask, + const char *verbose_prefix) { CPUX86State *env = &cpu->env; FeatureWordInfo *f = &feature_word_info[w]; @@ -5510,6 +5510,35 @@ static void mark_unavailable_features(X86CPU *cpu, FeatureWord w, uint64_t mask, } } +void mark_forced_on_features(X86CPU *cpu, FeatureWord w, uint64_t mask, + const char *verbose_prefix) +{ + CPUX86State *env = &cpu->env; + FeatureWordInfo *f = &feature_word_info[w]; + int i; + + if (!cpu->force_features) { + env->features[w] |= mask; + } + + cpu->forced_on_features[w] |= mask; + + if (!verbose_prefix) { + return; + } + + for (i = 0; i < 64; ++i) { + if ((1ULL << i) & mask) { + g_autofree char *feat_word_str = feature_word_description(f); + warn_report("%s: %s%s%s [bit %d]", + verbose_prefix, + feat_word_str, + f->feat_names[i] ? "." : "", + f->feat_names[i] ? f->feat_names[i] : "", i); + } + } +} + static void x86_cpuid_version_get_family(Object *obj, Visitor *v, const char *name, void *opaque, Error **errp) diff --git a/target/i386/cpu.h b/target/i386/cpu.h index a4c0531262ce..eb79daa0bf9f 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -2155,6 +2155,9 @@ struct ArchCPU { /* Features that were filtered out because of missing host capabilities */ FeatureWordArray filtered_features; + /* Features that are forced enabled by underlying hypervisor, e.g., TDX */ + FeatureWordArray forced_on_features; + /* Enable PMU CPUID bits. This can't be enabled by default yet because * it doesn't have ABI stability guarantees, as it passes all PMU CPUID * bits returned by GET_SUPPORTED_CPUID (that depend on host CPU and kernel @@ -2466,6 +2469,10 @@ void cpu_set_apic_feature(CPUX86State *env); void host_cpuid(uint32_t function, uint32_t count, uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx); bool cpu_has_x2apic_feature(CPUX86State *env); +void mark_unavailable_features(X86CPU *cpu, FeatureWord w, uint64_t mask, + const char *verbose_prefix); +void mark_forced_on_features(X86CPU *cpu, FeatureWord w, uint64_t mask, + const char *verbose_prefix); static inline bool x86_has_cpuid_0x1f(X86CPU *cpu) { diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c index 2b9a47020934..f6a4f3322e61 100644 --- a/target/i386/kvm/tdx.c +++ b/target/i386/kvm/tdx.c @@ -727,6 +727,104 @@ static uint32_t tdx_adjust_cpuid_features(X86ConfidentialGuest *cg, return value; } +static struct kvm_cpuid2 *tdx_fetch_cpuid(CPUState *cpu) +{ + struct kvm_cpuid2 *fetch_cpuid; + int size = KVM_MAX_CPUID_ENTRIES; + Error *local_err = NULL; + int r; + + do { + error_free(local_err); + local_err = NULL; + + fetch_cpuid = g_malloc0(sizeof(*fetch_cpuid) + + sizeof(struct kvm_cpuid_entry2) * size); + fetch_cpuid->nent = size; + r = tdx_vcpu_ioctl(cpu, KVM_TDX_GET_CPUID, 0, fetch_cpuid, &local_err); + if (r == -E2BIG) { + g_free(fetch_cpuid); + size = fetch_cpuid->nent; + } + } while (r == -E2BIG); + + if (r < 0) { + error_report_err(local_err); + return NULL; + } + + return fetch_cpuid; +} + +static int tdx_check_features(X86ConfidentialGuest *cg, CPUState *cs) +{ + uint64_t actual, requested, unavailable, forced_on; + g_autofree struct kvm_cpuid2 *fetch_cpuid; + const char *forced_on_prefix = NULL; + const char *unav_prefix = NULL; + struct kvm_cpuid_entry2 *entry; + X86CPU *cpu = X86_CPU(cs); + CPUX86State *env = &cpu->env; + FeatureWordInfo *wi; + FeatureWord w; + bool mismatch = false; + + fetch_cpuid = tdx_fetch_cpuid(cs); + if (!fetch_cpuid) { + return -1; + } + + if (cpu->check_cpuid || cpu->enforce_cpuid) { + unav_prefix = "TDX doesn't support requested feature"; + forced_on_prefix = "TDX forcibly sets the feature"; + } + + for (w = 0; w < FEATURE_WORDS; w++) { + wi = &feature_word_info[w]; + actual = 0; + + switch (wi->type) { + case CPUID_FEATURE_WORD: + entry = cpuid_find_entry(fetch_cpuid, wi->cpuid.eax, wi->cpuid.ecx); + if (!entry) { + /* + * If KVM doesn't report it means it's totally configurable + * by QEMU + */ + continue; + } + + actual = cpuid_entry_get_reg(entry, wi->cpuid.reg); + break; + case MSR_FEATURE_WORD: + /* + * TODO: + * validate MSR features when KVM has interface report them. + */ + continue; + } + + requested = env->features[w]; + unavailable = requested & ~actual; + mark_unavailable_features(cpu, w, unavailable, unav_prefix); + if (unavailable) { + mismatch = true; + } + + forced_on = actual & ~requested; + mark_forced_on_features(cpu, w, forced_on, forced_on_prefix); + if (forced_on) { + mismatch = true; + } + } + + if (cpu->enforce_cpuid && mismatch) { + return -1; + } + + return 0; +} + static int tdx_validate_attributes(TdxGuest *tdx, Error **errp) { if ((tdx->attributes & ~tdx_caps->supported_attrs)) { @@ -1087,4 +1185,5 @@ static void tdx_guest_class_init(ObjectClass *oc, void *data) x86_klass->kvm_type = tdx_kvm_type; x86_klass->cpu_instance_init = tdx_cpu_instance_init; x86_klass->adjust_cpuid_features = tdx_adjust_cpuid_features; + x86_klass->check_features = tdx_check_features; }
Use KVM_TDX_GET_CPUID to get the CPUIDs that are managed and enfored by TDX module for TD guest. Check QEMU's configuration against the fetched data. Print wanring message when 1. a feature is not supported but requested by QEMU or 2. QEMU doesn't want to expose a feature while it is enforced enabled. - If cpu->enforced_cpuid is not set, prints the warning message of both 1) and 2) and tweak QEMU's configuration. - If cpu->enforced_cpuid is set, quit if any case of 1) or 2). Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> --- target/i386/cpu.c | 33 ++++++++++++++- target/i386/cpu.h | 7 +++ target/i386/kvm/tdx.c | 99 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 137 insertions(+), 2 deletions(-)