x86/virt: Force GIF=1 prior to disabling SVM (for reboot flows)

Set GIF=1 prior to disabling SVM to ensure that INIT is recognized if the
kernel is disabling SVM in an emergency, e.g. if the kernel is about to
jump into a crash kernel or may reboot without doing a full CPU RESET.
If GIF is left cleared, the new kernel (or firmware) will be unabled to
awaken APs.  Eat faults on STGI (due to EFER.SVME=0) as it's possible
that SVM could be disabled via NMI shootdown between reading EFER.SVME
and executing STGI.

Link: https://lore.kernel.org/all/[email protected]
Cc: [email protected]
Cc: Andrew Cooper <[email protected]>
Cc: Tom Lendacky <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sean Christopherson <[email protected]>

0 files changed, 0 insertions, 0 deletions