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| author | Marc Zyngier <maz@kernel.org> | 2020-07-13 15:15:14 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2020-10-01 09:53:45 +0100 |
| commit | 452d62227958e149e5c7b0084a559c0957c3ff2a (patch) | |
| tree | 5f28be95ed0a4f5cebf3237ed5d33be3d4902d14 | |
| parent | 620cf45f7a516bf5fe9e5dce675a652e935c8bde (diff) | |
| download | linux-452d62227958e149e5c7b0084a559c0957c3ff2a.tar.gz | |
KVM: arm64: Restore missing ISB on nVHE __tlb_switch_to_guest
Commit a0e50aa3f4a8 ("KVM: arm64: Factor out stage 2 page table
data from struct kvm") dropped the ISB after __load_guest_stage2(),
only leaving the one that is required when the speculative AT
workaround is in effect.
As Andrew points it: "This alternative is 'backwards' to avoid a
double ISB as there is one in __load_guest_stage2 when the workaround
is active."
Restore the missing ISB, conditionned on the AT workaround not being
active.
Fixes: a0e50aa3f4a8 ("KVM: arm64: Factor out stage 2 page table data from struct kvm")
Reported-by: Andrew Scull <ascull@google.com>
Reported-by: Thomas Tai <thomas.tai@oracle.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/tlb.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/nvhe/tlb.c b/arch/arm64/kvm/hyp/nvhe/tlb.c index 69eae608d67081..b15d65a42042d2 100644 --- a/arch/arm64/kvm/hyp/nvhe/tlb.c +++ b/arch/arm64/kvm/hyp/nvhe/tlb.c @@ -31,7 +31,14 @@ static void __tlb_switch_to_guest(struct kvm_s2_mmu *mmu, isb(); } + /* + * __load_guest_stage2() includes an ISB only when the AT + * workaround is applied. Take care of the opposite condition, + * ensuring that we always have an ISB, but not two ISBs back + * to back. + */ __load_guest_stage2(mmu); + asm(ALTERNATIVE("isb", "nop", ARM64_WORKAROUND_SPECULATIVE_AT)); } static void __tlb_switch_to_host(struct tlb_inv_context *cxt) |