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Tsirkin" , Paolo Bonzini , Marcelo Tosatti , Yanjing Zhou Subject: Re: [PATCH v2 3/9] target/i386: Hide ARCH_CAPABILITIES for Hygon Message-ID: References: <20260810082956.1768042-1-zhang_wei@open-hieco.net> <20260810082956.1768042-4-zhang_wei@open-hieco.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260810082956.1768042-4-zhang_wei@open-hieco.net> Received-SPF: pass client-ip=192.198.163.8; envelope-from=zhao1.liu@intel.com; helo=mgamail.intel.com X-Spam_score_int: -46 X-Spam_score: -4.7 X-Spam_bar: ---- X-Spam_report: (-4.7 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.341, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, Aug 10, 2026 at 04:29:50PM +0800, Tina Zhang wrote: > Date: Mon, 10 Aug 2026 16:29:50 +0800 > From: Tina Zhang > Subject: [PATCH v2 3/9] target/i386: Hide ARCH_CAPABILITIES for Hygon > X-Mailer: git-send-email 2.43.7 > > IA32_ARCH_CAPABILITIES is an Intel-defined MSR. KVM can synthesize the > CPUID bit and read-only MSR for non-Intel guests, and QEMU already hides > that interface for AMD CPU models because Windows may not expect it on > AMD-compatible CPUs. > > Hygon Dhyana uses the HygonGenuine vendor string, so it currently skips > that AMD filter. If arch-capabilities=on is requested, QEMU can expose > CPUID.7.0.EDX[ARCH_CAPABILITIES] and the associated MSR feature word to > a Hygon guest. > > That creates a vendor-inconsistent CPU ABI: the guest sees an > AMD-compatible vendor and cache/topology interface, but also sees an > Intel-specific architectural capabilities MSR. Guests that choose CPU > mitigation or feature paths from the vendor can mis-handle that > combination; Windows is known to be sensitive to ARCH_CAPABILITIES on > AMD-compatible CPUs. > > Apply the same ARCH_CAPABILITIES hiding rule to Hygon CPUs when the vendor > CPU ABI compat gate is enabled. Keep arch_cap_always_on as the migration > escape hatch, and keep the old Hygon CPUID/MSR output for pc-11.0 and > older machine types via x-hygon-vendor-abi-fixes=false. Nit: pc-11.1? Same applies to the other commit messages. Thanks, Zhao