]> www.infradead.org Git - users/jedix/linux-maple.git/commit
x86/virt: Force GIF=1 prior to disabling SVM (for reboot flows)
authorSean Christopherson <seanjc@google.com>
Wed, 30 Nov 2022 23:36:48 +0000 (23:36 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 10 Mar 2023 08:34:13 +0000 (09:34 +0100)
commitc4765c973c1d83964cea75881d83040cfa4109da
treea679569954b828a99ac41a747e4e86a08bc220f6
parentb261024d7ea8aebfd1ac4a36d5d1ae0a62f1a97e
x86/virt: Force GIF=1 prior to disabling SVM (for reboot flows)

commit 6a3236580b0b1accc3976345e723104f74f6f8e6 upstream.

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/cbcb6f35-e5d7-c1c9-4db9-fe5cc4de579a@amd.com
Cc: stable@vger.kernel.org
Cc: Andrew Cooper <Andrew.Cooper3@citrix.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221130233650.1404148-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/include/asm/virtext.h