KVM: x86: Add SBPB support

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Add support for the AMD Selective Branch Predictor Barrier (SBPB) by
advertising the CPUID bit and handling PRED_CMD writes accordingly.

Note, like SRSO_NO and IBPB_BRTYPE before it, advertise support for SBPB
even if it's not enumerated by in the raw CPUID.  Some CPUs that gained
support via a uCode patch don't report SBPB via CPUID (the kernel forces
the flag).

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/a4ab1e7fe50096d50fde33e739ed2da40b41ea6a.1692919072.git.jpoimboe@kernel.org
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>

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This commit is contained in:

Josh Poimboeuf 2023-08-25 00:01:36 -07:00 • committed by Sean Christopherson

parent 6f0f23ef76

commit e47d86083c

3 changed files with 27 additions and 6 deletions

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1

arch/x86/kvm/cpuid.c

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3

arch/x86/kvm/cpuid.h

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29

arch/x86/kvm/x86.c

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