On Sun, Jan 06, 2013 at 04:12:54PM +0200, Gleb Natapov wrote:
On Fri, Jan 04, 2013 at 08:01:06PM -0200, Eduardo Habkost wrote:
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> Reviewed-by: Gleb Natapov <gleb@redhat.com> But see the question below.
--- 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} Why do we exclude PPRO_FEATURES/CPUID_EXT3_SVM from been checked?
I simply have no idea. I just have a few guesses: - PPRO_FEATURES was supposed to be CPUID_EXT2_AMD_ALIASES, as the user could want to expose vendor=AMD on a non-AMD host; - Maybe CPUID_EXT3_SVM was being excluded because the old code checked the host CPUID directly (instead of using GET_SUPPORTED_CPUID), so the SVM bit in the host CPU wouldn't tell us anything about nested SVM support. They are removed on in separate patches that follow, and then the check_feat field is removed completely.
+ };
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
-- Gleb.
-- Eduardo