Thread (19 messages) flat view 19 messages, 3 authors, 2021-03-23

Re: [PATCH 4/7] KVM: arm64: Add flush_all_cache_lines counter for kvm_stat

From: Marc Zyngier <maz@kernel.org>
Date: 2021-03-23 17:24:14
Also in: kvmarm

On Fri, 19 Mar 2021 16:17:08 +0000,
Yoan Picchi [off-list ref] wrote:
Add a counter that triggers when all the cache are flushed. This happens
when toggling caching for instance.
Which cache?
quoted hunk ↗ jump to hunk
Signed-off-by: Yoan Picchi <redacted>
---
 arch/arm64/include/asm/kvm_host.h | 1 +
 arch/arm64/kvm/guest.c            | 1 +
 arch/arm64/kvm/mmu.c              | 1 +
 3 files changed, 3 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 3609aa89d..e6967951f 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -547,6 +547,7 @@ static inline bool __vcpu_write_sys_reg_to_cpu(u64 val, int reg)
 
 struct kvm_vm_stat {
 	ulong remote_tlb_flush;
+	ulong flush_all_cache_lines;
 	ulong cached_page_invalidated;
 };
 
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index f6b1f0b63..d948c3bd2 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -41,6 +41,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	VCPU_STAT("regular_page_mapped", regular_page_mapped),
 	VCPU_STAT("huge_page_mapped", huge_page_mapped),
 	VM_STAT("remote_tlb_flush", remote_tlb_flush),
+	VM_STAT("flush_all_cache_lines", flush_all_cache_lines),
 	VM_STAT("cached_page_invalidated", cached_page_invalidated),
 	VCPU_STAT("exits", exits),
 	VCPU_STAT("halt_poll_success_ns", halt_poll_success_ns),
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index d6ddf5ab8..985b048df 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -181,6 +181,7 @@ static void stage2_flush_vm(struct kvm *kvm)
 	kvm_for_each_memslot(memslot, slots)
 		stage2_flush_memslot(kvm, memslot);
 
+	kvm->stat.flush_all_cache_lines++;
What additional information does this give over the other d-side flush
counter?

	M.

-- 
Without deviation from the norm, progress is not possible.

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