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[104.155.91.135]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-6a7e68c42c2sm5275845a12.14.2026.09.08.03.18.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Sep 2026 03:18:05 -0700 (PDT) Date: Tue, 8 Sep 2026 11:18:01 +0100 From: Vincent Donnefort To: Wei-Lin Chang Cc: maz@kernel.org, oupton@kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, kernel-team@android.com, fuad.tabba@linux.dev, qperret@google.com, keirf@google.com Subject: Re: [PATCH 04/20] KVM: arm64: Use block-level annotations when setting up the host stage-2 Message-ID: References: <20260803100904.3563942-1-vdonnefort@google.com> <20260803100904.3563942-5-vdonnefort@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260908_111808_593298_B7DE97B6 X-CRM114-Status: GOOD ( 21.76 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Sep 07, 2026 at 03:37:56PM +0100, Wei-Lin Chang wrote: > On Mon, Aug 03, 2026 at 11:08:48AM +0100, Vincent Donnefort wrote: > > [...] > > > +static int fix_host_ownership_walker(const struct kvm_pgtable_visit_ctx *ctx, > > + enum kvm_pgtable_walk_flags visit) > > +{ > > + struct fix_host_ownership_data *data = ctx->arg; > > + enum kvm_pgtable_prot prot = 0; > > + phys_addr_t phys = 0; > > + int ret; > > + > > + if (kvm_pte_valid(ctx->old)) > > + prot = kvm_pgtable_hyp_pte_prot(ctx->old); > > + > > + if (!prot) { > > + /* Unchanged region */ > > + if (!data->prot) > > + return 0; > > + > > + goto apply_ownership; > > + } > > + > > + phys = kvm_pte_to_phys(ctx->old); > > + if (!addr_is_memory(phys)) > > + return -EINVAL; > > + > > + /* We already know phys is contiguous as we walk the linear map */ > > + > > + if (prot != data->prot) > > + goto apply_ownership; > > + > > + /* Accumulate in the current region */ > > + data->size += kvm_granule_size(ctx->level); > > + > > + return 0; > > + > > +apply_ownership: > > + ret = __fix_host_ownership(data); > > + if (ret) > > + return ret; > > + > > + data->phys = phys; > > + data->size = kvm_granule_size(ctx->level); > > + data->prot = prot; > > + > > + return 0; > > +} > > I think this function can be simplified, if we check phys first: > > static int fix_host_ownership_walker(const struct kvm_pgtable_visit_ctx *ctx, > enum kvm_pgtable_walk_flags visit) > { > struct fix_host_ownership_data *data = ctx->arg; > enum kvm_pgtable_prot prot = 0; > phys_addr_t phys = 0; > int ret; > > if (kvm_pte_valid(ctx->old)) > prot = kvm_pgtable_hyp_pte_prot(ctx->old); > > if (prot) { > phys = kvm_pte_to_phys(ctx->old); > if (!addr_is_memory(phys)) > return -EINVAL; > } > > if (prot != data->prot) { > ret = __fix_host_ownership(data); > if (ret) > return ret; > > data->phys = phys; > data->size = kvm_granule_size(ctx->level); > data->prot = prot; > } else { > data->size += kvm_granule_size(ctx->level); > } > return 0; > } > > Did I miss anything? > > Thanks, > Wei-Lin Chang Indeed, I think it's my: if (prot != data->prot) goto apply_ownership that is clumsy. With if (prot == data->prot) { data->size += kvm_granule_size(); return 0; } (which is basically what you suggested) I can get rid of the label. -- Vincent