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KVM: SVM: adjust register allocation for __svm_vcpu_run()

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32-bit ABI uses RAX/RCX/RDX as its argument registers, so they are in
the way of instructions that hardcode their operands such as RDMSR/WRMSR
or VMLOAD/VMRUN/VMSAVE.

In preparation for moving vmload/vmsave to __svm_vcpu_run(), keep
the pointer to the struct vcpu_svm in %rdi.  In particular, it is now
possible to load svm->vmcb01.pa in %rax without clobbering the struct
vcpu_svm pointer.

No functional change intended.

Cc: stable@vger.kernel.org
Fixes: a149180fbc ("x86: Add magic AMD return-thunk")
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2022-10-28 17:30:07 -04:00
parent 16fdc1de16
commit f7ef280132
1 changed files with 20 additions and 20 deletions
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40
arch/x86/kvm/svm/vmenter.S
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@ -54,30 +54,30 @@ SYM_FUNC_START(__svm_vcpu_run)
/* Save @vmcb. */
push %_ASM_ARG1
/* Move @svm to RAX. */
mov %_ASM_ARG2, %_ASM_AX
/* Load guest registers. */
mov VCPU_RCX(%_ASM_AX), %_ASM_CX
mov VCPU_RDX(%_ASM_AX), %_ASM_DX
mov VCPU_RBX(%_ASM_AX), %_ASM_BX
mov VCPU_RBP(%_ASM_AX), %_ASM_BP
mov VCPU_RSI(%_ASM_AX), %_ASM_SI
mov VCPU_RDI(%_ASM_AX), %_ASM_DI
#ifdef CONFIG_X86_64
mov VCPU_R8 (%_ASM_AX), %r8
mov VCPU_R9 (%_ASM_AX), %r9
mov VCPU_R10(%_ASM_AX), %r10
mov VCPU_R11(%_ASM_AX), %r11
mov VCPU_R12(%_ASM_AX), %r12
mov VCPU_R13(%_ASM_AX), %r13
mov VCPU_R14(%_ASM_AX), %r14
mov VCPU_R15(%_ASM_AX), %r15
#endif
/* Move @svm to RDI. */
mov %_ASM_ARG2, %_ASM_DI
/* "POP" @vmcb to RAX. */
pop %_ASM_AX
/* Load guest registers. */
mov VCPU_RCX(%_ASM_DI), %_ASM_CX
mov VCPU_RDX(%_ASM_DI), %_ASM_DX
mov VCPU_RBX(%_ASM_DI), %_ASM_BX
mov VCPU_RBP(%_ASM_DI), %_ASM_BP
mov VCPU_RSI(%_ASM_DI), %_ASM_SI
#ifdef CONFIG_X86_64
mov VCPU_R8 (%_ASM_DI), %r8
mov VCPU_R9 (%_ASM_DI), %r9
mov VCPU_R10(%_ASM_DI), %r10
mov VCPU_R11(%_ASM_DI), %r11
mov VCPU_R12(%_ASM_DI), %r12
mov VCPU_R13(%_ASM_DI), %r13
mov VCPU_R14(%_ASM_DI), %r14
mov VCPU_R15(%_ASM_DI), %r15
#endif
mov VCPU_RDI(%_ASM_DI), %_ASM_DI
/* Enter guest mode */
sti