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From: Keqian Zhu <zhukeqian1@huawei.com>
To: <linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<kvmarm@lists.cs.columbia.edu>, <kvm@vger.kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>, James Morse <james.morse@arm.com>,
	Will Deacon <will@kernel.org>,
	"Suzuki K Poulose" <suzuki.poulose@arm.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Mark Brown <broonie@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Alexios Zavras <alexios.zavras@intel.com>,
	<liangpeng10@huawei.com>, <zhengxiang9@huawei.com>,
	<wanghaibin.wang@huawei.com>, Keqian Zhu <zhukeqian1@huawei.com>
Subject: [PATCH 08/12] KVM: Omit dirty log sync in log clear if initially all set
Date: Tue, 16 Jun 2020 17:35:49 +0800	[thread overview]
Message-ID: <20200616093553.27512-9-zhukeqian1@huawei.com> (raw)
In-Reply-To: <20200616093553.27512-1-zhukeqian1@huawei.com>

Synchronizing dirty log during log clear is useful only when the dirty
bitmap of userspace contains dirty bits that memslot dirty bitmap does
not contain, because we can sync new dirty bits to memslot dirty bitmap,
then we can clear them by the way and avoid reporting them to userspace
later.

With dirty bitmap "initially all set" feature, the above situation will
not appear if userspace logic is normal, so we can omit dirty log sync in
log clear. This is valuable when dirty log sync is a high-cost operation,
such as arm64 DBM.

Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
---
 virt/kvm/kvm_main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3722343fd460..6c147d6f9da6 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1554,7 +1554,8 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm,
 	    (log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63)))
 	    return -EINVAL;
 
-	kvm_arch_sync_dirty_log(kvm, memslot);
+	if (!kvm_dirty_log_manual_protect_and_init_set(kvm))
+		kvm_arch_sync_dirty_log(kvm, memslot);
 
 	flush = false;
 	dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
-- 
2.19.1


WARNING: multiple messages have this Message-ID (diff)
From: Keqian Zhu <zhukeqian1@huawei.com>
To: <linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<kvmarm@lists.cs.columbia.edu>, <kvm@vger.kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	liangpeng10@huawei.com, Alexios Zavras <alexios.zavras@intel.com>,
	Mark Brown <broonie@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <will@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH 08/12] KVM: Omit dirty log sync in log clear if initially all set
Date: Tue, 16 Jun 2020 17:35:49 +0800	[thread overview]
Message-ID: <20200616093553.27512-9-zhukeqian1@huawei.com> (raw)
In-Reply-To: <20200616093553.27512-1-zhukeqian1@huawei.com>

Synchronizing dirty log during log clear is useful only when the dirty
bitmap of userspace contains dirty bits that memslot dirty bitmap does
not contain, because we can sync new dirty bits to memslot dirty bitmap,
then we can clear them by the way and avoid reporting them to userspace
later.

With dirty bitmap "initially all set" feature, the above situation will
not appear if userspace logic is normal, so we can omit dirty log sync in
log clear. This is valuable when dirty log sync is a high-cost operation,
such as arm64 DBM.

Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
---
 virt/kvm/kvm_main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3722343fd460..6c147d6f9da6 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1554,7 +1554,8 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm,
 	    (log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63)))
 	    return -EINVAL;
 
-	kvm_arch_sync_dirty_log(kvm, memslot);
+	if (!kvm_dirty_log_manual_protect_and_init_set(kvm))
+		kvm_arch_sync_dirty_log(kvm, memslot);
 
 	flush = false;
 	dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
-- 
2.19.1

_______________________________________________
kvmarm mailing list
kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

WARNING: multiple messages have this Message-ID (diff)
From: Keqian Zhu <zhukeqian1@huawei.com>
To: <linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<kvmarm@lists.cs.columbia.edu>, <kvm@vger.kernel.org>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Keqian Zhu <zhukeqian1@huawei.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	liangpeng10@huawei.com, Alexios Zavras <alexios.zavras@intel.com>,
	zhengxiang9@huawei.com, Mark Brown <broonie@kernel.org>,
	James Morse <james.morse@arm.com>, Marc Zyngier <maz@kernel.org>,
	wanghaibin.wang@huawei.com, Thomas Gleixner <tglx@linutronix.de>,
	Will Deacon <will@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Julien Thierry <julien.thierry.kdev@gmail.com>
Subject: [PATCH 08/12] KVM: Omit dirty log sync in log clear if initially all set
Date: Tue, 16 Jun 2020 17:35:49 +0800	[thread overview]
Message-ID: <20200616093553.27512-9-zhukeqian1@huawei.com> (raw)
In-Reply-To: <20200616093553.27512-1-zhukeqian1@huawei.com>

Synchronizing dirty log during log clear is useful only when the dirty
bitmap of userspace contains dirty bits that memslot dirty bitmap does
not contain, because we can sync new dirty bits to memslot dirty bitmap,
then we can clear them by the way and avoid reporting them to userspace
later.

With dirty bitmap "initially all set" feature, the above situation will
not appear if userspace logic is normal, so we can omit dirty log sync in
log clear. This is valuable when dirty log sync is a high-cost operation,
such as arm64 DBM.

Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
---
 virt/kvm/kvm_main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3722343fd460..6c147d6f9da6 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1554,7 +1554,8 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm,
 	    (log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63)))
 	    return -EINVAL;
 
-	kvm_arch_sync_dirty_log(kvm, memslot);
+	if (!kvm_dirty_log_manual_protect_and_init_set(kvm))
+		kvm_arch_sync_dirty_log(kvm, memslot);
 
 	flush = false;
 	dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot);
-- 
2.19.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2020-06-16  9:37 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-16  9:35 [PATCH 00/12] KVM: arm64: Support stage2 hardware DBM Keqian Zhu
2020-06-16  9:35 ` Keqian Zhu
2020-06-16  9:35 ` Keqian Zhu
2020-06-16  9:35 ` [PATCH 01/12] KVM: arm64: Add some basic functions to support hw DBM Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35 ` [PATCH 02/12] KVM: arm64: Modify stage2 young mechanism " Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35 ` [PATCH 03/12] KVM: arm64: Report hardware dirty status of stage2 PTE if coverred Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-07-01 11:28   ` Steven Price
2020-07-01 11:28     ` Steven Price
2020-07-01 11:28     ` Steven Price
2020-07-02 11:28     ` zhukeqian
2020-07-02 11:28       ` zhukeqian
2020-07-02 11:28       ` zhukeqian
2020-06-16  9:35 ` [PATCH 04/12] KVM: arm64: Support clear DBM bit for PTEs Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35 ` [PATCH 05/12] KVM: arm64: Add KVM_CAP_ARM_HW_DIRTY_LOG capability Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35 ` [PATCH 06/12] KVM: arm64: Set DBM bit of PTEs during write protecting Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35 ` [PATCH 07/12] KVM: arm64: Scan PTEs to sync dirty log Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35 ` Keqian Zhu [this message]
2020-06-16  9:35   ` [PATCH 08/12] KVM: Omit dirty log sync in log clear if initially all set Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35 ` [PATCH 09/12] KVM: arm64: Steply write protect page table by mask bit Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35 ` [PATCH 10/12] KVM: arm64: Save stage2 PTE dirty status if it is coverred Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35 ` [PATCH 11/12] KVM: arm64: Support disable hw dirty log after enable Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35 ` [PATCH 12/12] KVM: arm64: Enable stage2 hardware DBM Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-16  9:35   ` Keqian Zhu
2020-06-18  4:13 ` [PATCH 00/12] KVM: arm64: Support " zhukeqian
2020-06-18  4:13   ` zhukeqian
2020-06-18  4:13   ` zhukeqian

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