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KVM: VMX: Access @flags as a 32-bit value in __vmx_vcpu_run()

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Access @flags using 32-bit operands when saving and testing @flags for
VMX_RUN_VMRESUME, as using 8-bit operands is unnecessarily fragile due
to relying on VMX_RUN_VMRESUME being in bits 0-7.  The behavior of
treating @flags a single byte is a holdover from when the param was
"bool launched", i.e. is not deliberate.

Cc: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20221119003747.2615229-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson
2022-11-19 00:37:47 +00:00
parent 7cb79f433e
commit 5a7a64779e
1 changed files with 4 additions and 4 deletions
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8
arch/x86/kvm/vmx/vmenter.S
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@@ -69,8 +69,8 @@ SYM_FUNC_START(__vmx_vcpu_run)
*/
push %_ASM_ARG2
/* Copy @flags to BL, _ASM_ARG3 is volatile. */
mov %_ASM_ARG3B, %bl
/* Copy @flags to EBX, _ASM_ARG3 is volatile. */
mov %_ASM_ARG3L, %ebx
lea (%_ASM_SP), %_ASM_ARG2
call vmx_update_host_rsp
@@ -106,7 +106,7 @@ SYM_FUNC_START(__vmx_vcpu_run)
mov (%_ASM_SP), %_ASM_AX
/* Check if vmlaunch or vmresume is needed */
testb $VMX_RUN_VMRESUME, %bl
test $VMX_RUN_VMRESUME, %ebx
/* Load guest registers. Don't clobber flags. */
mov VCPU_RCX(%_ASM_AX), %_ASM_CX
@@ -128,7 +128,7 @@ SYM_FUNC_START(__vmx_vcpu_run)
/* Load guest RAX. This kills the @regs pointer! */
mov VCPU_RAX(%_ASM_AX), %_ASM_AX
/* Check EFLAGS.ZF from 'testb' above */
/* Check EFLAGS.ZF from 'test VMX_RUN_VMRESUME' above */
jz .Lvmlaunch
/*