[PATCH 0/3] KVM: SEV: Add support for BTB Isolation

[Kim Phillips <kim.phillips@amd.com>]

This feature ensures SNP guest Branch Target Buffers (BTBs) are not
affected by context outside that guest.

The first patch fixes a longstanding bug where users couldn't select
Automatic IBRS on AMD machines using spectre_v2=eibrs on the kcmdline.

The second patch fixes another longstanding bug where users couldn't
select legacy / toggling SPEC_CTRL[IBRS] on AMD systems, which may
be used by users of the BTB Isolation feature.

The third patch adds support for the feature by adding it to the
supported features bitmask.

Based on git://git.kernel.org/pub/scm/virt/kvm/kvm.git next,
currently b1195183ed42 (tag: tags/kvm-7.0-1, kvm/queue, kvm/next).

This series also available here:

https://github.com/AMDESE/linux/tree/btb-isol-latest

Advance qemu bits (to add btb-isol=on/off switch) available here:

https://github.com/AMDESE/qemu/tree/btb-isol-latest

Qemu bits will be posted upstream once kernel bits are merged.
They depend on Naveen Rao's "target/i386: SEV: Add support for
enabling VMSA SEV features":

https://lore.kernel.org/qemu-devel/cover.1761648149.git.naveen@kernel.org/

Kim Phillips (3):
  cpu/bugs: Fix selecting Automatic IBRS using spectre_v2=eibrs
  cpu/bugs: Allow spectre_v2=ibrs on x86 vendors other than Intel
  KVM: SEV: Add support for SNP BTB Isolation

 arch/x86/include/asm/svm.h |  1 +
 arch/x86/kernel/cpu/bugs.c | 16 +++++++---------
 arch/x86/kvm/svm/sev.c     |  3 +++
 3 files changed, 11 insertions(+), 9 deletions(-)


base-commit: b1195183ed42f1522fae3fe44ebee3af437aa000
-- 
2.43.0