Rust, target/i386 changes for QEMU 10.1 soft freeze

[PULL 68/77] i386/cpu: Mark EBX/ECX/EDX in CPUID 0x80000000 leaf as reserved for Intel

Paolo Bonzini posted 77 patches 4 months ago

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Maintainers: "Philippe Mathieu-Daudé" <philmd@linaro.org>, "Daniel P. Berrangé" <berrange@redhat.com>, Kashyap Chamarthy <kchamart@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Marcelo Tosatti <mtosatti@redhat.com>, "Michael S. Tsirkin" <mst@redhat.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Richard Henderson <richard.henderson@linaro.org>, Eduardo Habkost <eduardo@habkost.net>, Cornelia Huck <cohuck@redhat.com>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Eric Blake <eblake@redhat.com>, Markus Armbruster <armbru@redhat.com>, Manos Pitsidianakis <manos.pitsidianakis@linaro.org>, Zhao Liu <zhao1.liu@intel.com>, Cameron Esfahani <dirty@apple.com>, Roman Bolshakov <rbolshakov@ddn.com>, Phil Dennis-Jordan <phil@philjordan.eu>, Reinoud Zandijk <reinoud@netbsd.org>, Sunil Muthuswamy <sunilmut@microsoft.com>, Warner Losh <imp@bsdimp.com>, Kyle Evans <kevans@freebsd.org>, Ed Maste <emaste@freebsd.org>, Li-Wen Hsu <lwhsu@freebsd.org>, "Alex Bennée" <alex.bennee@linaro.org>, Thomas Huth <thuth@redhat.com>

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[PULL 68/77] i386/cpu: Mark EBX/ECX/EDX in CPUID 0x80000000 leaf as reserved for Intel

Posted by Paolo Bonzini 4 months ago

From: Zhao Liu <zhao1.liu@intel.com>

Per SDM,

80000000H EAX Maximum Input Value for Extended Function CPUID Information.
          EBX Reserved.
          ECX Reserved.
          EDX Reserved.

EBX/ECX/EDX in CPUID 0x80000000 leaf are reserved. Intel is using 0x0
leaf to encode vendor.

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Tao Su <tao1.su@linux.intel.com>
Link: https://lore.kernel.org/r/20250627035129.2755537-2-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/cpu.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 4f0c9734461..ae508fa962d 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -8280,9 +8280,15 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         break;
     case 0x80000000:
         *eax = env->cpuid_xlevel;
-        *ebx = env->cpuid_vendor1;
-        *edx = env->cpuid_vendor2;
-        *ecx = env->cpuid_vendor3;
+
+        if (cpu->vendor_cpuid_only_v2 &&
+            (IS_INTEL_CPU(env) || IS_ZHAOXIN_CPU(env))) {
+            *ebx = *ecx = *edx = 0;
+        } else {
+            *ebx = env->cpuid_vendor1;
+            *edx = env->cpuid_vendor2;
+            *ecx = env->cpuid_vendor3;
+        }
         break;
     case 0x80000001:
         *eax = env->cpuid_version;
-- 
2.50.0