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[82.30.61.225]) by smtp.gmail.com with ESMTPSA id m12-20020adfe0cc000000b0021d4155cd6fsm11820459wri.53.2022.07.04.07.27.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Jul 2022 07:27:48 -0700 (PDT) Date: Mon, 4 Jul 2022 15:27:46 +0100 From: "Dr. David Alan Gilbert" To: Joao Martins Cc: qemu-devel@nongnu.org, Igor Mammedov , Eduardo Habkost , "Michael S. Tsirkin" , Richard Henderson , Alex Williamson , Paolo Bonzini , Ani Sinha , Marcel Apfelbaum , Suravee Suthikulpanit Subject: Re: [PATCH v6 10/10] i386/pc: restrict AMD only enforcing of valid IOVAs to new machine type Message-ID: References: <20220701161014.3850-1-joao.m.martins@oracle.com> <20220701161014.3850-11-joao.m.martins@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220701161014.3850-11-joao.m.martins@oracle.com> User-Agent: Mutt/2.2.6 (2022-06-05) Received-SPF: pass client-ip=170.10.129.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Joao Martins (joao.m.martins@oracle.com) wrote: > The added enforcing is only relevant in the case of AMD where the > range right before the 1TB is restricted and cannot be DMA mapped > by the kernel consequently leading to IOMMU INVALID_DEVICE_REQUEST > or possibly other kinds of IOMMU events in the AMD IOMMU. > > Although, there's a case where it may make sense to disable the > IOVA relocation/validation when migrating from a > non-valid-IOVA-aware qemu to one that supports it. > > Relocating RAM regions to after the 1Tb hole has consequences for > guest ABI because we are changing the memory mapping, so make > sure that only new machine enforce but not older ones. > > Signed-off-by: Joao Martins Thanks for keeping the migration compatibility, so for migration: Acked-by: Dr. David Alan Gilbert > --- > hw/i386/pc.c | 6 ++++-- > hw/i386/pc_piix.c | 2 ++ > hw/i386/pc_q35.c | 2 ++ > include/hw/i386/pc.h | 1 + > 4 files changed, 9 insertions(+), 2 deletions(-) > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c > index 07025b510540..f99e16a5db4b 100644 > --- a/hw/i386/pc.c > +++ b/hw/i386/pc.c > @@ -1013,9 +1013,10 @@ void pc_memory_init(PCMachineState *pcms, > /* > * The HyperTransport range close to the 1T boundary is unique to AMD > * hosts with IOMMUs enabled. Restrict the ram-above-4g relocation > - * to above 1T to AMD vCPUs only. > + * to above 1T to AMD vCPUs only. @enforce_valid_iova is only false in > + * older machine types (<= 7.0) for compatibility purposes. > */ > - if (IS_AMD_CPU(&cpu->env)) { > + if (IS_AMD_CPU(&cpu->env) && pcmc->enforce_valid_iova) { > pc_set_amd_above_4g_mem_start(pcms, pci_hole64_size); > > /* > @@ -1950,6 +1951,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data) > pcmc->has_reserved_memory = true; > pcmc->kvmclock_enabled = true; > pcmc->enforce_aligned_dimm = true; > + pcmc->enforce_valid_iova = true; > /* BIOS ACPI tables: 128K. Other BIOS datastructures: less than 4K reported > * to be used at the moment, 32K should be enough for a while. */ > pcmc->acpi_data_size = 0x20000 + 0x8000; > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c > index f3c726e42400..504ddd0deece 100644 > --- a/hw/i386/pc_piix.c > +++ b/hw/i386/pc_piix.c > @@ -444,9 +444,11 @@ DEFINE_I440FX_MACHINE(v7_1, "pc-i440fx-7.1", NULL, > > static void pc_i440fx_7_0_machine_options(MachineClass *m) > { > + PCMachineClass *pcmc = PC_MACHINE_CLASS(m); > pc_i440fx_7_1_machine_options(m); > m->alias = NULL; > m->is_default = false; > + pcmc->enforce_valid_iova = false; > compat_props_add(m->compat_props, hw_compat_7_0, hw_compat_7_0_len); > compat_props_add(m->compat_props, pc_compat_7_0, pc_compat_7_0_len); > } > diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c > index 5a4a737fe203..4b747c59c19a 100644 > --- a/hw/i386/pc_q35.c > +++ b/hw/i386/pc_q35.c > @@ -381,8 +381,10 @@ DEFINE_Q35_MACHINE(v7_1, "pc-q35-7.1", NULL, > > static void pc_q35_7_0_machine_options(MachineClass *m) > { > + PCMachineClass *pcmc = PC_MACHINE_CLASS(m); > pc_q35_7_1_machine_options(m); > m->alias = NULL; > + pcmc->enforce_valid_iova = false; > compat_props_add(m->compat_props, hw_compat_7_0, hw_compat_7_0_len); > compat_props_add(m->compat_props, pc_compat_7_0, pc_compat_7_0_len); > } > diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h > index 568c226d3034..3a873ff69499 100644 > --- a/include/hw/i386/pc.h > +++ b/include/hw/i386/pc.h > @@ -118,6 +118,7 @@ struct PCMachineClass { > bool has_reserved_memory; > bool enforce_aligned_dimm; > bool broken_reserved_end; > + bool enforce_valid_iova; > > /* generate legacy CPU hotplug AML */ > bool legacy_cpu_hotplug; > -- > 2.17.2 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK