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From: Will Deacon <will@kernel.org>
To: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Yanan Wang <wangyanan55@huawei.com>,
	Marc Zyngier <maz@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Gavin Shan <gshan@redhat.com>,
	Quentin Perret <qperret@google.com>,
	wanghaibin.wang@huawei.com, zhukeqian1@huawei.com,
	yuzenghui@huawei.com
Subject: Re: [RFC PATCH v3 1/2] KVM: arm64: Move CMOs from user_mem_abort to the fault handlers
Date: Wed, 7 Apr 2021 21:57:02 +0100	[thread overview]
Message-ID: <20210407205701.GA16198@willie-the-truck> (raw)
In-Reply-To: <cd6c8a86-b7b2-3d3e-121a-c9d1cb23c4b3@arm.com>

On Wed, Apr 07, 2021 at 04:31:31PM +0100, Alexandru Elisei wrote:
> On 3/26/21 3:16 AM, Yanan Wang wrote:
> > We currently uniformly permorm CMOs of D-cache and I-cache in function
> > user_mem_abort before calling the fault handlers. If we get concurrent
> > guest faults(e.g. translation faults, permission faults) or some really
> > unnecessary guest faults caused by BBM, CMOs for the first vcpu are
> 
> I can't figure out what BBM means.

Oh, I know that one! BBM means "Break Before Make". Not to be confused with
DBM (Dirty Bit Management) or BFM (Bit Field Move).

Will

WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: kvm@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
	linux-kernel@vger.kernel.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH v3 1/2] KVM: arm64: Move CMOs from user_mem_abort to the fault handlers
Date: Wed, 7 Apr 2021 21:57:02 +0100	[thread overview]
Message-ID: <20210407205701.GA16198@willie-the-truck> (raw)
In-Reply-To: <cd6c8a86-b7b2-3d3e-121a-c9d1cb23c4b3@arm.com>

On Wed, Apr 07, 2021 at 04:31:31PM +0100, Alexandru Elisei wrote:
> On 3/26/21 3:16 AM, Yanan Wang wrote:
> > We currently uniformly permorm CMOs of D-cache and I-cache in function
> > user_mem_abort before calling the fault handlers. If we get concurrent
> > guest faults(e.g. translation faults, permission faults) or some really
> > unnecessary guest faults caused by BBM, CMOs for the first vcpu are
> 
> I can't figure out what BBM means.

Oh, I know that one! BBM means "Break Before Make". Not to be confused with
DBM (Dirty Bit Management) or BFM (Bit Field Move).

Will
_______________________________________________
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: Will Deacon <will@kernel.org>
To: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Yanan Wang <wangyanan55@huawei.com>,
	Marc Zyngier <maz@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Gavin Shan <gshan@redhat.com>,
	Quentin Perret <qperret@google.com>,
	wanghaibin.wang@huawei.com, zhukeqian1@huawei.com,
	yuzenghui@huawei.com
Subject: Re: [RFC PATCH v3 1/2] KVM: arm64: Move CMOs from user_mem_abort to the fault handlers
Date: Wed, 7 Apr 2021 21:57:02 +0100	[thread overview]
Message-ID: <20210407205701.GA16198@willie-the-truck> (raw)
In-Reply-To: <cd6c8a86-b7b2-3d3e-121a-c9d1cb23c4b3@arm.com>

On Wed, Apr 07, 2021 at 04:31:31PM +0100, Alexandru Elisei wrote:
> On 3/26/21 3:16 AM, Yanan Wang wrote:
> > We currently uniformly permorm CMOs of D-cache and I-cache in function
> > user_mem_abort before calling the fault handlers. If we get concurrent
> > guest faults(e.g. translation faults, permission faults) or some really
> > unnecessary guest faults caused by BBM, CMOs for the first vcpu are
> 
> I can't figure out what BBM means.

Oh, I know that one! BBM means "Break Before Make". Not to be confused with
DBM (Dirty Bit Management) or BFM (Bit Field Move).

Will

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

  reply	other threads:[~2021-04-07 20:57 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26  3:16 [RFC PATCH v3 0/2] KVM: arm64: Improve efficiency of stage2 page table Yanan Wang
2021-03-26  3:16 ` Yanan Wang
2021-03-26  3:16 ` Yanan Wang
2021-03-26  3:16 ` [RFC PATCH v3 1/2] KVM: arm64: Move CMOs from user_mem_abort to the fault handlers Yanan Wang
2021-03-26  3:16   ` Yanan Wang
2021-03-26  3:16   ` Yanan Wang
2021-04-07 15:31   ` Alexandru Elisei
2021-04-07 15:31     ` Alexandru Elisei
2021-04-07 15:31     ` Alexandru Elisei
2021-04-07 20:57     ` Will Deacon [this message]
2021-04-07 20:57       ` Will Deacon
2021-04-07 20:57       ` Will Deacon
2021-04-08  9:23     ` wangyanan (Y)
2021-04-08  9:23       ` wangyanan (Y)
2021-04-08  9:23       ` wangyanan (Y)
2021-04-08 15:59       ` Alexandru Elisei
2021-04-08 15:59         ` Alexandru Elisei
2021-04-08 15:59         ` Alexandru Elisei
2021-03-26  3:16 ` [RFC PATCH v3 2/2] KVM: arm64: Distinguish cases of memcache allocations completely Yanan Wang
2021-03-26  3:16   ` Yanan Wang
2021-03-26  3:16   ` Yanan Wang
2021-04-07 15:35   ` Alexandru Elisei
2021-04-07 15:35     ` Alexandru Elisei
2021-04-07 15:35     ` Alexandru Elisei
2021-04-08  9:31     ` wangyanan (Y)
2021-04-08  9:31       ` wangyanan (Y)
2021-04-08  9:31       ` wangyanan (Y)

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