Description: KVM: SEV: only access GHCB fields once
References:
 https://bugzilla.redhat.com/show_bug.cgi?id=2213802
 https://patchew.org/linux/20230804173355.51753-1-pbonzini@redhat.com/
 https://patchew.org/linux/20230804173355.51753-1-pbonzini@redhat.com/20230804173355.51753-3-pbonzini@redhat.com/
Notes:
 carnil> Commit fixes 291bd20d5d88 ("KVM: SVM: Add initial support for a
 carnil> VMGEXIT VMEXIT") in 5.11-rc1.
 carnil> Fixed in 6.4.11 for 6.4.y.
Bugs:
upstream: released (6.5-rc6) [7588dbcebcbf0193ab5b76987396d0254270b04a]
6.1-upstream-stable: released (6.1.46) [5bdf1c1f346c81996b6e36b5efd5c92aeda4fbe4]
5.10-upstream-stable: N/A "Vulnerable code not present"
4.19-upstream-stable: N/A "Vulnerable code not present"
sid: released (6.4.11-1)
6.1-bookworm-security: released (6.1.52-1)
5.10-bullseye-security: N/A "Vulnerable code not present"
4.19-buster-security: N/A "Vulnerable code not present"