On Mon, Aug 10, 2026 at 04:29:48PM +0800, Tina Zhang wrote: > Date: Mon, 10 Aug 2026 16:29:48 +0800 > From: Tina Zhang <[email protected]> > Subject: [PATCH v2 1/9] target/i386: Sync AMD CPUID aliases for Hygon > X-Mailer: git-send-email 2.43.7 > > AMD defines CPUID[0x80000001].EDX bits as aliases for a subset of > CPUID[1].EDX. QEMU currently synchronizes those aliases only when the > guest CPU vendor is AuthenticAMD. > > Hygon Dhyana uses the HygonGenuine vendor string, but implements the > same AMD-compatible extended CPUID feature aliases. This can leave QEMU > advertising a feature in CPUID[1].EDX while the matching extended alias > in CPUID[0x80000001].EDX stays clear. This inconsistent CPUID state can > confuse guest OS feature detection. > > Apply the alias synchronization to Hygon CPUs as well. Gate the new > behavior with x-hygon-vendor-abi-fixes and disable it for pc-11.0 and ^^^^^^^ nit: pc-11.1 ?
> older machine types, because the CPUID result is guest-visible ABI and > must remain migration-compatible. > > Add qtest coverage for the Dhyana model, including the compat property. > > Signed-off-by: Tina Zhang <[email protected]> > Tested-by: Yongwei Xu <[email protected]> > --- > hw/i386/pc.c | 5 ++ > hw/i386/pc_piix.c | 1 + > hw/i386/pc_q35.c | 1 + > include/hw/i386/pc.h | 3 ++ > target/i386/cpu.c | 10 ++-- > target/i386/cpu.h | 13 +++++ > tests/qtest/test-x86-cpuid-compat.c | 76 +++++++++++++++++++++++++++++ > 7 files changed, 106 insertions(+), 3 deletions(-) > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > index f064aa2b3e..2b4e322b2f 100644 > --- a/hw/i386/pc.c > +++ b/hw/i386/pc.c > @@ -74,6 +74,11 @@ > #include "hw/xen/xen-bus.h" > #endif > > +GlobalProperty pc_compat_11_1[] = { > + { TYPE_X86_CPU, "x-hygon-vendor-abi-fixes", "false" }, > +}; > +const size_t pc_compat_11_1_len = G_N_ELEMENTS(pc_compat_11_1); > + compat machine property is already on the master branch, so this patch need to be rebased. > GlobalProperty pc_compat_11_0[] = {}; > const size_t pc_compat_11_0_len = G_N_ELEMENTS(pc_compat_11_0); > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c > index 82457bdb16..8e58f2a7ee 100644 > --- a/hw/i386/pc_piix.c > +++ b/hw/i386/pc_piix.c > @@ -438,6 +438,7 @@ DEFINE_I440FX_MACHINE_AS_LATEST(11, 1); > static void pc_i440fx_machine_11_0_options(MachineClass *m) > { > pc_i440fx_machine_11_1_options(m); pc_i440fx_machine_11_1_options() has added pc_compat_11_1... > + compat_props_add(m->compat_props, pc_compat_11_1, pc_compat_11_1_len); ...so taht now we don't need ao do this again. > compat_props_add(m->compat_props, hw_compat_11_0, hw_compat_11_0_len); > compat_props_add(m->compat_props, pc_compat_11_0, pc_compat_11_0_len); > } > diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c > index 6c1e4eff5f..fd4366f51f 100644 > --- a/hw/i386/pc_q35.c > +++ b/hw/i386/pc_q35.c > @@ -393,6 +393,7 @@ DEFINE_Q35_MACHINE_AS_LATEST(11, 1); > static void pc_q35_machine_11_0_options(MachineClass *m) > { > pc_q35_machine_11_1_options(m); > + compat_props_add(m->compat_props, pc_compat_11_1, pc_compat_11_1_len); ditto. > compat_props_add(m->compat_props, hw_compat_11_0, hw_compat_11_0_len); > compat_props_add(m->compat_props, pc_compat_11_0, pc_compat_11_0_len); > } Overall, LGTM except rebasing :). Regards, Zhao
