Hi Paolo,
A gentle ping on this series. Any comments would be appreciated.
Thanks,
Tina
On 8/24/2026 12:53 PM, Tina Zhang wrote:
Hygon Dhyana uses the HygonGenuine vendor string, but a number of
guest-visible and KVM-facing interfaces follow AMD-compatible behavior.
QEMU currently keys several of these paths only on AuthenticAMD, so Hygon
guests can see vendor-inconsistent CPUID/MSR state or use the wrong KVM
PMU/MCE handling paths.
This series makes those checks explicit for Hygon where appropriate.
Guest-visible CPU ABI changes are gated by the new
x-hygon-vendor-abi-fixes property. The property defaults to true for new
machine types and is disabled for pc-11.1 and older, so existing machine
types keep their previous Hygon ABI for migration compatibility.
The KVM injected-MCE and PMU path changes are not CPUID model table
changes. They make QEMU use the AMD-compatible runtime handling that
Linux/KVM already uses for Hygon.
The series covers:
* AMD CPUID[0x80000001].EDX aliases for Hygon
* hiding Intel cache CPUID leaves 2 and 4 for Hygon
* hiding IA32_ARCH_CAPABILITIES for Hygon unless old ABI requires it
* AMD MCE status encoding for Hygon memory-failure injection
* AMD PMU MSR setup/save/restore paths for Hygon
* disabling Intel-style MCA broadcast for Hygon injected MCEs
* AMD IOMMU HT GPA hole layout for Hygon on new machine types
* AMD legacy cache fallback for Hygon when legacy-cache=on
* AMD-shaped default ucode-rev value for Hygon
Changes in v3:
* Rebased onto QEMU master at v11.1.0-453-geea8fe61b8. Use the
pc_compat_11_1 infrastructure already present upstream and remove the
duplicate compatibility wiring from the i440fx and q35 11.0 machine
options. Preserve the old Hygon ABI through pc-11.1 and update the
affected commit messages accordingly. (Zhao)
* Split the PMU change into a no-functional-change vendor-family
refactoring patch followed by the Hygon-specific change. (Zhao)
* Fold enforce_amd_1tb_hole and x-hygon-vendor-abi-fixes into the IOMMU
HT GPA hole helper and update its comment. Use explicit pc-q35-11.2
and pc-q35-11.1 machine versions in the functional tests and include
those versions in the test names. (Zhao)
* Remove the redundant vendor-specific comment from the ucode-rev
default path. (Zhao)
* Update the hygon_vendor_abi_fixes field comment to follow the style of
other machine-type compatibility fields.
* Add Reviewed-by tags from Zhao Liu to the Hygon MCE status, MCE
broadcast, and ucode-rev patches.
Changes in v2:
* Rebased onto v11.1.0-rc3. Moved the compatibility property to
pc_compat_11_1 and wired it into the i440fx and q35 11.1 machine
options. (Zhao)
* Patch 1: removed the single-use CPUID-alias helper and checked Hygon
directly at the call site. Also updated the hygon_vendor_abi_fixes
field comment to emphasize that it is a machine-type compatibility
option. (Zhao)
* Patch 4: removed the single-use MCE-status helper and checked Hygon
directly at the call site. (Zhao)
* Patch 5: reworked the PMU vendor checks around a common PMU vendor-family
abstraction, covering host/guest compatibility, PMU initialization,
and PMU MSR save/restore. (Zhao)
* Collected Reviewed-by tags for patches 2, 3, and 8.
Tested with:
ninja -C build
build/pyvenv/bin/meson test -C build --print-errorlogs \
qemu:qtest-x86_64/test-x86-cpuid-compat \
qemu:func-x86_64-mem_addr_space
Tina Zhang (10):
target/i386: Sync AMD CPUID aliases for Hygon
target/i386: Hide Intel cache CPUID leaves for Hygon
target/i386: Hide ARCH_CAPABILITIES for Hygon
target/i386/kvm: Use AMD MCE status encoding for Hygon
target/i386/kvm: Classify PMU vendor families
target/i386/kvm: Use AMD PMU MSR paths for Hygon
target/i386: Do not broadcast injected MCEs for Hygon
hw/i386: Reserve AMD IOMMU HT GPA range for Hygon
target/i386: Use AMD legacy cache fallback for Hygon
target/i386: Use AMD ucode-rev default for Hygon
hw/i386/pc.c | 30 ++++--
target/i386/cpu.c | 68 +++++++++----
target/i386/cpu.h | 12 +++
target/i386/helper.c | 2 +-
target/i386/kvm/kvm.c | 75 +++++++++++----
.../functional/x86_64/test_mem_addr_space.py | 36 +++++++
tests/qtest/test-x86-cpuid-compat.c | 95 +++++++++++++++++++
7 files changed, 275 insertions(+), 43 deletions(-)
