On Wed, Nov 09, 2022, Paolo Bonzini wrote:
In preparation for moving vmload/vmsave to __svm_vcpu_run,
__svm_vcpu_run()
keep the pointer to the struct vcpu_svm in %rdi. This way it is possible to load svm->vmcb01.pa in %rax without clobbering the pointer to svm itself.
If you feel like doing fixup before pushing, add a note to call out that avoiding RAX will also be "necessary" to play nice with loading/storing MSR_SPEC_CTRL? When fiddling with this code, I found the RDMSR/WRMSR clobbers to be far more problematic than the VMCB pointers.
No functional change intended.
Cc: stable@vger.kernel.org Fixes: a149180fbcf3 ("x86: Add magic AMD return-thunk") Signed-off-by: Paolo Bonzini pbonzini@redhat.com
Reviewed-by: Sean Christopherson seanjc@google.com