Re: [RESEND PATCH v5 10/11] KVM: arm64: Invalidate the table entries upon a range
From: Gavin Shan <hidden>
Date: 2023-07-05 00:52:23
Also in:
kvm, kvm-riscv, kvmarm, linux-mips, linux-riscv, lkml
On 6/22/23 03:50, Raghavendra Rao Ananta wrote:
Currently, during the operations such as a hugepage collapse, KVM would flush the entire VM's context using 'vmalls12e1is' TLBI operation. Specifically, if the VM is faulting on many hugepages (say after dirty-logging), it creates a performance penalty for the guest whose pages have already been faulted earlier as they would have to refill their TLBs again. Instead, leverage kvm_tlb_flush_vmid_range() for table entries. If the system supports it, only the required range will be flushed. Else, it'll fallback to the previous mechanism. Signed-off-by: Raghavendra Rao Ananta <redacted> --- arch/arm64/kvm/hyp/pgtable.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
Reviewed-by: Gavin Shan <redacted>
quoted hunk ↗ jump to hunk
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index df8ac14d9d3d4..50ef7623c54db 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c@@ -766,7 +766,8 @@ static bool stage2_try_break_pte(const struct kvm_pgtable_visit_ctx *ctx, * value (if any). */ if (kvm_pte_table(ctx->old, ctx->level)) - kvm_call_hyp(__kvm_tlb_flush_vmid, mmu); + kvm_tlb_flush_vmid_range(mmu, ctx->addr, + kvm_granule_size(ctx->level)); else if (kvm_pte_valid(ctx->old)) kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, ctx->addr, ctx->level);
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