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[PATCH 0/2] target/i386: allow using named CPU modeles with user mode em
From: |
Paolo Bonzini |
Subject: |
[PATCH 0/2] target/i386: allow using named CPU modeles with user mode emulation |
Date: |
Mon, 19 Jun 2023 00:21:07 +0200 |
When running qemu-i386 even with -cpu Nehalem (aka x86_64-v2), it raises the
warning
TCG doesn't support requested feature: CPUID.80000001H:EDX.lm [bit 29]
Likewise using qemu-x86_64 with -cpu Haswell, it raises warnings for
TCG doesn't support requested feature: CPUID.01H:ECX.pcid [bit 17]
TCG doesn't support requested feature: CPUID.01H:ECX.x2apic [bit 21]
TCG doesn't support requested feature: CPUID.01H:ECX.tsc-deadline [bit 24]
TCG doesn't support requested feature: CPUID.07H:EBX.invpcid [bit 10]
Even though x86_64-v3 is the level that qemu-user is supposed to provide.
These are two related problems:
- for Haswell, the 4 missing features are only relevant to code running
in kernel mode; we can ignore them and mark them as supported even
though they are not. The supported features are only used to print
the warnings
- for qemu-i386, the issue is that the i386 target is not about running
programs on a 32-bit processor, but rather running programs using the
32-bit kernel ABI on any processor; the behavior of the processor in
compatibility (32-bit) mode is independent of the LM feature. Therefore,
LM can also be treated as a feature that is only relevant in kernel
mode.
Other CPU models have warnings for the ARCH_CAPABILITIES MSR; hide
them as well in a similar manner.
Based-on: <20230618215114.107337-1-pbonzini@redhat.com>
Paolo Bonzini (2):
target/i386: ignore ARCH_CAPABILITIES features in user mode emulation
target/i386: ignore CPL0-specific features in user mode emulation
target/i386/cpu.c | 95 ++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 86 insertions(+), 9 deletions(-)
--
2.40.1
- [PATCH 0/2] target/i386: allow using named CPU modeles with user mode emulation,
Paolo Bonzini <=