KVM: x86/mmu: Locally cache whether a PFN is host MMIO when making a SPTE

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When making a SPTE, cache whether or not the target PFN is host MMIO in
order to avoid multiple rounds of the slow path of kvm_is_mmio_pfn(), e.g.
hitting pat_pfn_immune_to_uc_mtrr() in particular can be problematic.  KVM
currently avoids multiple calls by virtue of the two users being mutually
exclusive (.get_mt_mask() is Intel-only, shadow_me_value is AMD-only), but
that won't hold true if/when KVM needs to detect host MMIO mappings for
other reasons, e.g. for mitigating the MMIO Stale Data vulnerability.

No functional change intended.

Tested-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Link: https://lore.kernel.org/r/20250523011756.3243624-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

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Sean Christopherson 2025-05-22 18:17:53 -07:00

parent c126b46e6f

commit ffe9d7966d

1 changed files with 18 additions and 4 deletions

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arch/x86/kvm/mmu/spte.c

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