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From: Oliver Upton <oliver.upton@linux.dev>
To: Fuad Tabba <tabba@google.com>
Cc: kvmarm@lists.linux.dev, maz@kernel.org, will@kernel.org,
	qperret@google.com, seanjc@google.com, alexandru.elisei@arm.com,
	catalin.marinas@arm.com, philmd@linaro.org, james.morse@arm.com,
	suzuki.poulose@arm.com, mark.rutland@arm.com, broonie@kernel.org,
	joey.gouly@arm.com, rananta@google.com, smostafa@google.com
Subject: Re: [PATCH v3 11/31] KVM: arm64: Remove locking from EL2 allocation fast-paths
Date: Fri, 19 Apr 2024 20:42:26 +0000	[thread overview]
Message-ID: <ZiLXMo1nFkgXGS-H@linux.dev> (raw)
In-Reply-To: <20240419075941.4085061-12-tabba@google.com>

On Fri, Apr 19, 2024 at 08:59:21AM +0100, Fuad Tabba wrote:
> From: Will Deacon <will@kernel.org>
> 
> hyp_{get,put}_page() are called extensively from the page-table code
> to adjust reference counts on page-table pages. As a small step towards
> removing reader serialisation on these paths, drop the 'hyp_pool' lock
> in the case where the refcount remains positive, only taking the lock
> if the page is to be freed back to the allocator.

Surely the ordering of these patches is wrong... The refcount accessors
are non-atomic until patch 27.

-- 
Thanks,
Oliver

  reply	other threads:[~2024-04-19 20:42 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-19  7:59 [PATCH v3 00/31] KVM: arm64: Preamble for pKVM Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 01/31] KVM: arm64: Initialize the kvm host data's fpsimd_state pointer in pKVM Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 02/31] KVM: arm64: Move guest_owns_fp_regs() to increase its scope Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 03/31] KVM: arm64: Refactor checks for FP state ownership Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 04/31] KVM: arm64: Do not re-initialize the KVM lock Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 05/31] KVM: arm64: Issue CMOs when tearing down guest s2 pages Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 06/31] KVM: arm64: Avoid BUG-ing from the host abort path Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 07/31] KVM: arm64: Check for PTE validity when checking for executable/cacheable Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 08/31] KVM: arm64: Avoid BBM when changing only s/w bits in Stage-2 PTE Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 09/31] KVM: arm64: Support TLB invalidation in guest context Fuad Tabba
2024-04-19 20:54   ` Oliver Upton
2024-04-22  8:11     ` Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 10/31] KVM: arm64: Do not map the host fpsimd state to hyp in pKVM Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 11/31] KVM: arm64: Remove locking from EL2 allocation fast-paths Fuad Tabba
2024-04-19 20:42   ` Oliver Upton [this message]
2024-04-22  8:09     ` Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 12/31] KVM: arm64: Prevent kmemleak from accessing .hyp.data Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 13/31] KVM: arm64: Fix comment for __pkvm_vcpu_init_traps() Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 14/31] KVM: arm64: Change kvm_handle_mmio_return() return polarity Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 15/31] KVM: arm64: Move setting the page as dirty out of the critical section Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 16/31] KVM: arm64: Simplify vgic-v3 hypercalls Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 17/31] KVM: arm64: Add is_pkvm_initialized() helper Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 18/31] KVM: arm64: Introduce and use predicates that check for protected VMs Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 19/31] KVM: arm64: Move pstate reset value definitions to kvm_arm.h Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 20/31] KVM: arm64: Clarify rationale for ZCR_EL1 value restored on guest exit Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 21/31] KVM: arm64: Refactor calculating SVE state size to use helpers Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 22/31] KVM: arm64: Move some kvm_psci functions to a shared header Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 23/31] KVM: arm64: Refactor reset_mpidr() to extract its computation Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 24/31] KVM: arm64: Refactor kvm_vcpu_enable_ptrauth() for hyp use Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 25/31] KVM: arm64: Introduce hyp_rwlock_t Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 26/31] KVM: arm64: Add atomics-based checking refcount implementation at EL2 Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 27/31] KVM: arm64: Use atomic refcount helpers for 'struct hyp_page::refcount' Fuad Tabba
2024-04-19 20:52   ` Oliver Upton
2024-04-22  8:10     ` Fuad Tabba
2024-04-22 13:08       ` Fuad Tabba
2024-04-22 20:46         ` Oliver Upton
2024-04-22 23:44           ` Will Deacon
2024-04-23  1:15             ` Oliver Upton
2024-04-19  7:59 ` [PATCH v3 28/31] KVM: arm64: Reformat/beautify PTP hypercall documentation Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 29/31] KVM: arm64: Rename firmware pseudo-register documentation file Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 30/31] KVM: arm64: Document the KVM/arm64-specific calls in hypercalls.rst Fuad Tabba
2024-04-19  7:59 ` [PATCH v3 31/31] KVM: arm64: Force injection of a data abort on NISV MMIO exit Fuad Tabba
2024-04-19 20:28   ` Oliver Upton
2024-04-22  8:07     ` Fuad Tabba

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