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author | Sean Christopherson <seanjc@google.com> | 2022-05-26 21:08:13 +0000 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-06-10 10:01:30 -0400 |
commit | 0cbc60d44c35b1070eb4070b499164d27d050576 (patch) | |
tree | ce1cfd691810beb5465fded0c0a621e6737b138b /arch/x86/kvm/kvm_emulate.h | |
parent | a5ba67b42f07952ec45755bbdd66d7c6e49f555c (diff) | |
download | linux-0cbc60d44c35b1070eb4070b499164d27d050576.tar.bz2 |
KVM: x86: Use 16-bit fields to track dirty/valid emulator GPRs
Use a u16 instead of a u32 to track the dirty/valid status of GPRs in the
emulator. Unlike struct kvm_vcpu_arch, x86_emulate_ctxt tracks only the
"true" GPRs, i.e. doesn't include RIP in its array, and so only needs to
track 16 registers.
Note, maxing out at 16 GPRs is a fundamental property of x86-64 and will
not change barring a massive architecture update. Legacy x86 ModRM and
SIB encodings use 3 bits for GPRs, i.e. support 8 registers. x86-64 uses
a single bit in the REX prefix for each possible reference type to double
the number of supported GPRs to 16 registers (4 bits).
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220526210817.3428868-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/kvm_emulate.h')
-rw-r--r-- | arch/x86/kvm/kvm_emulate.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index bc3f8295c8c8..3a65d6ea7fe6 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -356,9 +356,9 @@ struct x86_emulate_ctxt { u8 lock_prefix; u8 rep_prefix; /* bitmaps of registers in _regs[] that can be read */ - u32 regs_valid; + u16 regs_valid; /* bitmaps of registers in _regs[] that have been written */ - u32 regs_dirty; + u16 regs_dirty; /* modrm */ u8 modrm; u8 modrm_mod; |