From patchwork Tue Feb 13 09:32:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 13554760 Received: from out-174.mta1.migadu.com (out-174.mta1.migadu.com [95.215.58.174]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D36CB224C6 for ; Tue, 13 Feb 2024 09:33:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.174 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707816799; cv=none; b=s/lc2nAkXwk9Bo3J/ptznD9GfOzd/CS+kdqy6ngVwpLdyqVOsVPIW9yW98ErVqnZu3cf6tjoKravWz/hO028m5QjMySSYYqf/nAI9Ts0FtKs6+Z0AcUNup1JqgWFj8p3pHwsLWuqwlgLLjdFM7/VFLY672YpfvT2ZCZ5xzN3WQs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707816799; c=relaxed/simple; bh=bwAh/HjIrt1hqUnlvYVrZwrrMVLgoGSwee3tzVmP50s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OG2muiUO6/q1zmWw9Bii7hocnIxsWn1D5Ucadbe08R4FZ1X9qzXfjuO0+GuMrtgJAZ3DxGj6OeU7J22oa56O03DGWu4gHSjhUTH/a8+cmiRctTKE3jlvrJ/jhSctm5IjnQtPE27F9OI2qSp0K8i0OuEMU2dgBMrqSAxjDElWmNs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=vo8RB2qf; arc=none smtp.client-ip=95.215.58.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="vo8RB2qf" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1707816794; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=cyUnvVECpp/8iTljvXmQPWzrvEO1ZBGnoQKIdU51DBU=; b=vo8RB2qfGqEonVTQPePSakr2QqTty/7P7NdKqNQyptvl5bDfkijfU1kXX6vvVTY6dFU+c3 HogKV3EfdrrPBOPunsoemPi/WzmFuHTnAflQrWwQm5WlW5x/RrSrKna+v5kRUktY0CUQnw ARsEvSc++Dh03U+obakDaYrOC/LfaT8= From: Oliver Upton To: kvmarm@lists.linux.dev Cc: kvm@vger.kernel.org, Marc Zyngier , James Morse , Suzuki K Poulose , Zenghui Yu , linux-kernel@vger.kernel.org, Oliver Upton Subject: [PATCH v2 01/23] KVM: arm64: Add tracepoints + stats for LPI cache effectiveness Date: Tue, 13 Feb 2024 09:32:38 +0000 Message-ID: <20240213093250.3960069-2-oliver.upton@linux.dev> In-Reply-To: <20240213093250.3960069-1-oliver.upton@linux.dev> References: <20240213093250.3960069-1-oliver.upton@linux.dev> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT LPI translation and injection has been shown to have a significant impact on the performance of VM workloads, so it probably makes sense to add some signals in this area. Introduce the concept of a KVM tracepoint that associates with a VM stat and use it for the LPI translation cache tracepoints. It isn't too uncommon for a kernel hacker to attach to tracepoints, while at the same time userspace may open a 'binary stats' FD to peek at the corresponding VM stats. Signed-off-by: Oliver Upton --- arch/arm64/include/asm/kvm_host.h | 3 ++ arch/arm64/kvm/guest.c | 5 ++- arch/arm64/kvm/vgic/trace.h | 66 +++++++++++++++++++++++++++++++ arch/arm64/kvm/vgic/vgic-its.c | 14 ++++++- include/linux/kvm_host.h | 4 ++ 5 files changed, 89 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 21c57b812569..6f88b76373a5 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -966,6 +966,9 @@ static inline bool __vcpu_write_sys_reg_to_cpu(u64 val, int reg) struct kvm_vm_stat { struct kvm_vm_stat_generic generic; + u64 vgic_its_trans_cache_hit; + u64 vgic_its_trans_cache_miss; + u64 vgic_its_trans_cache_victim; }; struct kvm_vcpu_stat { diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index aaf1d4939739..354d67251fc2 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -30,7 +30,10 @@ #include "trace.h" const struct _kvm_stats_desc kvm_vm_stats_desc[] = { - KVM_GENERIC_VM_STATS() + KVM_GENERIC_VM_STATS(), + STATS_DESC_COUNTER(VM, vgic_its_trans_cache_hit), + STATS_DESC_COUNTER(VM, vgic_its_trans_cache_miss), + STATS_DESC_COUNTER(VM, vgic_its_trans_cache_victim) }; const struct kvm_stats_header kvm_vm_stats_header = { diff --git a/arch/arm64/kvm/vgic/trace.h b/arch/arm64/kvm/vgic/trace.h index 83c64401a7fc..ff6423f22c91 100644 --- a/arch/arm64/kvm/vgic/trace.h +++ b/arch/arm64/kvm/vgic/trace.h @@ -27,6 +27,72 @@ TRACE_EVENT(vgic_update_irq_pending, __entry->vcpu_id, __entry->irq, __entry->level) ); +TRACE_EVENT(vgic_its_trans_cache_hit, + TP_PROTO(__u64 db_addr, __u32 device_id, __u32 event_id, __u32 intid), + TP_ARGS(db_addr, device_id, event_id, intid), + + TP_STRUCT__entry( + __field( __u64, db_addr ) + __field( __u32, device_id ) + __field( __u32, event_id ) + __field( __u32, intid ) + ), + + TP_fast_assign( + __entry->db_addr = db_addr; + __entry->device_id = device_id; + __entry->event_id = event_id; + __entry->intid = intid; + ), + + TP_printk("DB: %016llx, device_id %u, event_id %u, intid %u", + __entry->db_addr, __entry->device_id, __entry->event_id, + __entry->intid) +); + +TRACE_EVENT(vgic_its_trans_cache_miss, + TP_PROTO(__u64 db_addr, __u32 device_id, __u32 event_id), + TP_ARGS(db_addr, device_id, event_id), + + TP_STRUCT__entry( + __field( __u64, db_addr ) + __field( __u32, device_id ) + __field( __u32, event_id ) + ), + + TP_fast_assign( + __entry->db_addr = db_addr; + __entry->device_id = device_id; + __entry->event_id = event_id; + ), + + TP_printk("DB: %016llx, device_id %u, event_id %u", + __entry->db_addr, __entry->device_id, __entry->event_id) +); + +TRACE_EVENT(vgic_its_trans_cache_victim, + TP_PROTO(__u64 db_addr, __u32 device_id, __u32 event_id, __u32 intid), + TP_ARGS(db_addr, device_id, event_id, intid), + + TP_STRUCT__entry( + __field( __u64, db_addr ) + __field( __u32, device_id ) + __field( __u32, event_id ) + __field( __u32, intid ) + ), + + TP_fast_assign( + __entry->db_addr = db_addr; + __entry->device_id = device_id; + __entry->event_id = event_id; + __entry->intid = intid; + ), + + TP_printk("DB: %016llx, device_id %u, event_id %u, intid %u", + __entry->db_addr, __entry->device_id, __entry->event_id, + __entry->intid) +); + #endif /* _TRACE_VGIC_H */ #undef TRACE_INCLUDE_PATH diff --git a/arch/arm64/kvm/vgic/vgic-its.c b/arch/arm64/kvm/vgic/vgic-its.c index e2764d0ffa9f..59179268ac2d 100644 --- a/arch/arm64/kvm/vgic/vgic-its.c +++ b/arch/arm64/kvm/vgic/vgic-its.c @@ -20,6 +20,7 @@ #include #include +#include "trace.h" #include "vgic.h" #include "vgic-mmio.h" @@ -636,8 +637,11 @@ static void vgic_its_cache_translation(struct kvm *kvm, struct vgic_its *its, * to the interrupt, so drop the potential reference on what * was in the cache, and increment it on the new interrupt. */ - if (cte->irq) + if (cte->irq) { + KVM_VM_TRACE_EVENT(kvm, vgic_its_trans_cache_victim, cte->db, + cte->devid, cte->eventid, cte->irq->intid); __vgic_put_lpi_locked(kvm, cte->irq); + } vgic_get_irq_kref(irq); @@ -767,8 +771,14 @@ int vgic_its_inject_cached_translation(struct kvm *kvm, struct kvm_msi *msi) db = (u64)msi->address_hi << 32 | msi->address_lo; irq = vgic_its_check_cache(kvm, db, msi->devid, msi->data); - if (!irq) + if (!irq) { + KVM_VM_TRACE_EVENT(kvm, vgic_its_trans_cache_miss, db, msi->devid, + msi->data); return -EWOULDBLOCK; + } + + KVM_VM_TRACE_EVENT(kvm, vgic_its_trans_cache_hit, db, msi->devid, + msi->data, irq->intid); raw_spin_lock_irqsave(&irq->irq_lock, flags); irq->pending_latch = true; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 7e7fd25b09b3..846b447b6798 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1927,6 +1927,10 @@ struct _kvm_stats_desc { HALT_POLL_HIST_COUNT), \ STATS_DESC_IBOOLEAN(VCPU_GENERIC, blocking) +#define KVM_VM_TRACE_EVENT(vm, event, ...) \ + ((vm)->stat.event)++; trace_## event(__VA_ARGS__) + + extern struct dentry *kvm_debugfs_dir; ssize_t kvm_stats_read(char *id, const struct kvm_stats_header *header,