[libvirt] [PATCH qom-cpu 05/11] target-i386: check/enforce: Fix CPUID leaf numbers on error messages

Eduardo Habkost
2013-01-04T22:01:06Z

The -cpu check/enforce warnings are printing incorrect information about the
missing flags. There are no feature flags on CPUID leaves 0 and 0x80000000, but
there were references to 0 and 0x80000000 in the table at
kvm_check_features_against_host().

This changes the model_features_t struct to contain the register number as
well, so the error messages print the correct CPUID leaf+register information,
instead of wrong CPUID leaf numbers.

This also changes the format of the error messages, so they follow the
"CPUID.<leaf>.<register>.<name> [bit <offset>]" convention used on Intel
documentation. Example output:

$ qemu-system-x86_64 -machine pc-1.0,accel=kvm -cpu Opteron_G4,+ia64,enforce
warning: host doesn't support requested feature: CPUID.01H:EDX.ia64 [bit 30]
warning: host doesn't support requested feature: CPUID.01H:ECX.xsave [bit 26]
warning: host doesn't support requested feature: CPUID.01H:ECX.avx [bit 28]
warning: host doesn't support requested feature: CPUID.80000001H:ECX.abm [bit 5]
warning: host doesn't support requested feature: CPUID.80000001H:ECX.sse4a [bit 6]
warning: host doesn't support requested feature: CPUID.80000001H:ECX.misalignsse [bit 7]
warning: host doesn't support requested feature: CPUID.80000001H:ECX.3dnowprefetch [bit 8]
warning: host doesn't support requested feature: CPUID.80000001H:ECX.xop [bit 11]
warning: host doesn't support requested feature: CPUID.80000001H:ECX.fma4 [bit 16]
Unable to find x86 CPU definition
$

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org

Changes v2:
- Coding style fixes
- Add assert() for invalid register numbers on
unavailable_host_feature()
---
target-i386/cpu.c | 42 +++++++++++++++++++++++++++++++++---------
target-i386/cpu.h | 3 +++
2 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index e916ae0..c3e5db8 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -124,6 +124,25 @@ static const char *cpuid_7_0_ebx_feature_name[] = {
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
};

+const char *get_register_name_32(unsigned int reg)
+{
+ static const char *reg_names[CPU_NB_REGS32] = {
+ [R_EAX] = "EAX",
+ [R_ECX] = "ECX",
+ [R_EDX] = "EDX",
+ [R_EBX] = "EBX",
+ [R_ESP] = "ESP",
+ [R_EBP] = "EBP",
+ [R_ESI] = "ESI",
+ [R_EDI] = "EDI",
+ };
+
+ if (reg > CPU_NB_REGS32) {
+ return NULL;
+ }
+ return reg_names[reg];
+}
+
/* collects per-function cpuid data
*/
typedef struct model_features_t {
@@ -132,7 +151,8 @@ typedef struct model_features_t {
uint32_t check_feat;
const char **flag_names;
uint32_t cpuid;
- } model_features_t;
+ int reg;
+} model_features_t;

int check_cpuid = 0;
int enforce_cpuid = 0;
@@ -923,10 +943,13 @@ static int unavailable_host_feature(struct model_features_t *f, uint32_t mask)

for (i = 0; i < 32; ++i)
if (1 << i & mask) {
- fprintf(stderr, "warning: host cpuid %04x_%04x lacks requested"
- " flag '%s' [0x%08x]\n",
- f->cpuid >> 16, f->cpuid & 0xffff,
- f->flag_names[i] ? f->flag_names[i] : "[reserved]", mask);
+ const char *reg = get_register_name_32(f->reg);
+ assert(reg);
+ fprintf(stderr, "warning: host doesn't support requested feature: "
+ "CPUID.%02XH:%s%s%s [bit %d]\n",
+ f->cpuid, reg,
+ f->flag_names[i] ? "." : "",
+ f->flag_names[i] ? f->flag_names[i] : "", i);
break;
}
return 0;
@@ -945,13 +968,14 @@ static int kvm_check_features_against_host(x86_def_t *guest_def)
int rv, i;
struct model_features_t ft[] = {
{&guest_def->features, &host_def.features,
- ~0, feature_name, 0x00000000},
+ ~0, feature_name, 0x00000001, R_EDX},
{&guest_def->ext_features, &host_def.ext_features,
- ~CPUID_EXT_HYPERVISOR, ext_feature_name, 0x00000001},
+ ~CPUID_EXT_HYPERVISOR, ext_feature_name, 0x00000001, R_ECX},
{&guest_def->ext2_features, &host_def.ext2_features,
- ~PPRO_FEATURES, ext2_feature_name, 0x80000000},
+ ~PPRO_FEATURES, ext2_feature_name, 0x80000001, R_EDX},
{&guest_def->ext3_features, &host_def.ext3_features,
- ~CPUID_EXT3_SVM, ext3_feature_name, 0x80000001}};
+ ~CPUID_EXT3_SVM, ext3_feature_name, 0x80000001, R_ECX}
+ };

assert(kvm_enabled());

diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 27c8d0c..ab81a5c 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -1221,4 +1221,7 @@ void cpu_report_tpr_access(CPUX86State *env, TPRAccess access);
void enable_kvm_pv_eoi(void);
void disable_kvm_mmu_op(void);

+/* Return name of 32-bit register, from a R_* constant */
+const char *get_register_name_32(unsigned int reg);
+
#endif /* CPU_I386_H */
--
1.7.11.7