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[PATCH 1/3] i386: hvf: Adds support for INVTSC cpuid bit
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From: |
Phil Dennis-Jordan |
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Subject: |
[PATCH 1/3] i386: hvf: Adds support for INVTSC cpuid bit |
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Date: |
Fri, 22 Sep 2023 16:09:12 +0200 |
This patch adds the INVTSC bit to the Hypervisor.framework accelerator's
CPUID bit passthrough allow-list. Previously, specifying +invtsc in the CPU
configuration would fail with the following warning despite the host CPU
advertising the feature:
qemu-system-x86_64: warning: host doesn't support requested feature:
CPUID.80000007H:EDX.invtsc [bit 8]
x86 macOS itself relies on a fixed rate TSC for its own Mach absolute time
timestamp mechanism, so there's no reason we can't enable this bit for guests.
Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu>
---
target/i386/hvf/x86_cpuid.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/target/i386/hvf/x86_cpuid.c b/target/i386/hvf/x86_cpuid.c
index 7323a7a94b..d2721bd2a7 100644
--- a/target/i386/hvf/x86_cpuid.c
+++ b/target/i386/hvf/x86_cpuid.c
@@ -145,6 +145,10 @@ uint32_t hvf_get_supported_cpuid(uint32_t func, uint32_t
idx,
CPUID_EXT3_3DNOWPREFETCH | CPUID_EXT3_OSVW | CPUID_EXT3_XOP |
CPUID_EXT3_FMA4 | CPUID_EXT3_TBM;
break;
+ case 0x80000007:
+ edx &= CPUID_APM_INVTSC;
+ eax = ebx = ecx = 0;
+ break;
default:
return 0;
}
--
2.36.1