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Thu, 13 Mar 2025 09:31:44 +0000 Date: Thu, 13 Mar 2025 09:31:42 +0000 Message-ID: <86ldt9nuo1.wl-maz@kernel.org> From: Marc Zyngier To: Vincent Donnefort Cc: oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, qperret@google.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH v3 2/3] KVM: arm64: Distinct pKVM teardown memcache for stage-2 In-Reply-To: References: <20250307113411.469018-1-vdonnefort@google.com> <20250307113411.469018-3-vdonnefort@google.com> <87plim7hgc.wl-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/29.4 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: vdonnefort@google.com, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, qperret@google.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Thu, 13 Mar 2025 09:13:45 +0000, Vincent Donnefort wrote: > > On Wed, Mar 12, 2025 at 08:59:15AM +0000, Marc Zyngier wrote: > > On Fri, 07 Mar 2025 11:34:10 +0000, > > Vincent Donnefort wrote: > > > > > > In order to account for memory dedicated to the stage-2 page-tables, use > > > a separated memcache when tearing down the VM. > > > > > > Signed-off-by: Vincent Donnefort > > > > > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > > > index 12691ae23d4c..ace3969e8106 100644 > > > --- a/arch/arm64/include/asm/kvm_host.h > > > +++ b/arch/arm64/include/asm/kvm_host.h > > > @@ -246,6 +246,7 @@ typedef unsigned int pkvm_handle_t; > > > struct kvm_protected_vm { > > > pkvm_handle_t handle; > > > struct kvm_hyp_memcache teardown_mc; > > > + struct kvm_hyp_memcache stage2_teardown_mc; > > > bool enabled; > > > }; > > > > > > diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c > > > index 3927fe52a3dd..15f8d5315959 100644 > > > --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c > > > +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c > > > @@ -678,7 +678,7 @@ teardown_donated_memory(struct kvm_hyp_memcache *mc, void *addr, size_t size) > > > > > > int __pkvm_teardown_vm(pkvm_handle_t handle) > > > { > > > - struct kvm_hyp_memcache *mc; > > > + struct kvm_hyp_memcache *mc, *stage2_mc; > > > struct pkvm_hyp_vm *hyp_vm; > > > struct kvm *host_kvm; > > > unsigned int idx; > > > @@ -706,7 +706,8 @@ int __pkvm_teardown_vm(pkvm_handle_t handle) > > > > > > /* Reclaim guest pages (including page-table pages) */ > > > mc = &host_kvm->arch.pkvm.teardown_mc; > > > - reclaim_guest_pages(hyp_vm, mc); > > > + stage2_mc = &host_kvm->arch.pkvm.stage2_teardown_mc; > > > + reclaim_guest_pages(hyp_vm, stage2_mc); > > > > This looks odd. What counts as stage-2 pages here? Or is it that > > reclaim_guest_pages() is very badly named? > > Yes, this is a naming issue here. How about > > reclaim_pgtable_pages(hyp_vm, stage2_mc); LGTM. > > Then I can probably drop that /* Push the metadata pages to the teardown > memcache */ comment as it is clear what is pgtable and what is meta-data? Yeah, the comments are actively getting in the way. Thanks, M. -- Without deviation from the norm, progress is not possible.