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author | Marc Zyngier <maz@kernel.org> | 2023-04-26 20:23:30 +0300 |
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committer | Oliver Upton <oliver.upton@linux.dev> | 2023-05-16 20:39:19 +0300 |
commit | a12ab1378a88b38f3af8b1a899b7d8526324ba6f (patch) | |
tree | 67c2fefbd6c0014b4ad71496b341fb11585183bf /arch/arm64/kvm/hyp/vhe | |
parent | 6acf51666d039857421b6f8a3660301c82649fa5 (diff) | |
download | linux-a12ab1378a88b38f3af8b1a899b7d8526324ba6f.tar.xz |
KVM: arm64: Use local TLBI on permission relaxation
Broadcast TLB invalidations (TLBIs) targeting the Inner Shareable
Domain are usually less performant than their non-shareable variant.
In particular, we observed some implementations that take
millliseconds to complete parallel broadcasted TLBIs.
It's safe to use non-shareable TLBIs when relaxing permissions on a
PTE in the KVM case. According to the ARM ARM (0487I.a) section
D8.13.1 "Using break-before-make when updating translation table
entries", permission relaxation does not need break-before-make.
Specifically, R_WHZWS states that these are the only changes that
require a break-before-make sequence: changes of memory type
(Shareability or Cacheability), address changes, or changing the block
size.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Link: https://lore.kernel.org/r/20230426172330.1439644-13-ricarkol@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Diffstat (limited to 'arch/arm64/kvm/hyp/vhe')
-rw-r--r-- | arch/arm64/kvm/hyp/vhe/tlb.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/vhe/tlb.c b/arch/arm64/kvm/hyp/vhe/tlb.c index 24cef9b87f9e..e69da550cdc5 100644 --- a/arch/arm64/kvm/hyp/vhe/tlb.c +++ b/arch/arm64/kvm/hyp/vhe/tlb.c @@ -111,6 +111,38 @@ void __kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, __tlb_switch_to_host(&cxt); } +void __kvm_tlb_flush_vmid_ipa_nsh(struct kvm_s2_mmu *mmu, + phys_addr_t ipa, int level) +{ + struct tlb_inv_context cxt; + + dsb(nshst); + + /* Switch to requested VMID */ + __tlb_switch_to_guest(mmu, &cxt); + + /* + * We could do so much better if we had the VA as well. + * Instead, we invalidate Stage-2 for this IPA, and the + * whole of Stage-1. Weep... + */ + ipa >>= 12; + __tlbi_level(ipas2e1, ipa, level); + + /* + * We have to ensure completion of the invalidation at Stage-2, + * since a table walk on another CPU could refill a TLB with a + * complete (S1 + S2) walk based on the old Stage-2 mapping if + * the Stage-1 invalidation happened first. + */ + dsb(nsh); + __tlbi(vmalle1); + dsb(nsh); + isb(); + + __tlb_switch_to_host(&cxt); +} + void __kvm_tlb_flush_vmid(struct kvm_s2_mmu *mmu) { struct tlb_inv_context cxt; |