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target/i386: implement RDPID in TCG

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RDPID corresponds to a RDMSR(TSC_AUX); however, it is unprivileged
so for user-mode emulation we must provide the value that the kernel
places in the MSR.  For Linux, it is a combination of the current CPU
and the current NUMA node, both of which can be retrieved with getcpu(2).
Also try sched_getcpu(), which might be there on the BSDs.  If there is
no portable way to retrieve the current CPU id from userspace, return 0.

RDTSCP is reimplemented as RDTSC + RDPID ECX; the differences in terms
of serializability are not relevant to QEMU.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2023-06-21 00:47:31 +02:00
parent 53b9b4cc9f
commit 6750485bf4
5 changed files with 46 additions and 13 deletions
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10
target/i386/cpu.c
View file

@ -661,9 +661,17 @@ void x86_cpu_vendor_words2str(char *dst, uint32_t vendor1,
/* missing:
CPUID_7_0_EBX_HLE
CPUID_7_0_EBX_INVPCID, CPUID_7_0_EBX_RTM */
#if defined CONFIG_SOFTMMU || defined CONFIG_LINUX
#define TCG_7_0_ECX_RDPID CPUID_7_0_ECX_RDPID
#else
#define TCG_7_0_ECX_RDPID 0
#endif
#define TCG_7_0_ECX_FEATURES (CPUID_7_0_ECX_UMIP | CPUID_7_0_ECX_PKU | \
/* CPUID_7_0_ECX_OSPKE is dynamic */ \
CPUID_7_0_ECX_LA57 | CPUID_7_0_ECX_PKS | CPUID_7_0_ECX_VAES)
CPUID_7_0_ECX_LA57 | CPUID_7_0_ECX_PKS | CPUID_7_0_ECX_VAES | \
TCG_7_0_ECX_RDPID)
#define TCG_7_0_EDX_FEATURES CPUID_7_0_EDX_FSRM
#define TCG_7_1_EAX_FEATURES (CPUID_7_1_EAX_FZRM | CPUID_7_1_EAX_FSRS | \
CPUID_7_1_EAX_FSRC)