KVM: SVM: Explicitly require FLUSHBYASID to enable SEV support

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Add a sanity check that FLUSHBYASID is available if SEV is supported in
hardware, as SEV (and beyond) guests are bound to a single ASID, i.e. KVM
can't "flush" by assigning a new, fresh ASID to the guest.  If FLUSHBYASID
isn't supported for some bizarre reason, KVM would completely fail to do
TLB flushes for SEV+ guests (see pre_svm_run() and pre_sev_run()).

Cc: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20231018193617.1895752-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

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Sean Christopherson 2023-10-18 12:36:17 -07:00

parent 176bfc5b17

commit 770d6aa2e4

1 changed files with 5 additions and 2 deletions

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arch/x86/kvm/svm/sev.c

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