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([2a01:e0a:f0e:9070:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a6d1188c6esm9027449f8f.81.2025.06.23.04.47.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 23 Jun 2025 04:47:56 -0700 (PDT) Message-ID: Date: Mon, 23 Jun 2025 13:47:55 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 11/19] intel_iommu: Handle PASID entry adding Content-Language: en-US To: Zhenzhong Duan , qemu-devel@nongnu.org Cc: alex.williamson@redhat.com, clg@redhat.com, mst@redhat.com, jasowang@redhat.com, peterx@redhat.com, ddutile@redhat.com, jgg@nvidia.com, nicolinc@nvidia.com, shameerali.kolothum.thodi@huawei.com, joao.m.martins@oracle.com, clement.mathieu--drif@eviden.com, kevin.tian@intel.com, yi.l.liu@intel.com, chao.p.peng@intel.com, Yi Sun , Paolo Bonzini , Richard Henderson , Eduardo Habkost , Marcel Apfelbaum References: <20250620071813.55571-1-zhenzhong.duan@intel.com> <20250620071813.55571-12-zhenzhong.duan@intel.com> From: Eric Auger In-Reply-To: <20250620071813.55571-12-zhenzhong.duan@intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=eric.auger@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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: , Reply-To: eric.auger@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Hi Zhenzhong, On 6/20/25 9:18 AM, Zhenzhong Duan wrote: > When guest modifies a PASID entry, QEMU will capture the guest pasid selective > pasid cache invalidation, allocate or remove a VTDAddressSpace instance per the > invalidation reasons: > > a) a present pasid entry moved to non-present > b) a present pasid entry to be a present entry > c) a non-present pasid entry moved to present > > This handles c). As you use the replay terminology in the patch, please explain what it means in that case and how the patch achieve above goal. > > Signed-off-by: Yi Liu > Signed-off-by: Yi Sun > Signed-off-by: Zhenzhong Duan > --- > hw/i386/intel_iommu_internal.h | 1 + > hw/i386/intel_iommu.c | 169 ++++++++++++++++++++++++++++++++- > 2 files changed, 169 insertions(+), 1 deletion(-) > > diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h > index 01c881ed4d..025787b3b9 100644 > --- a/hw/i386/intel_iommu_internal.h > +++ b/hw/i386/intel_iommu_internal.h > @@ -558,6 +558,7 @@ typedef struct VTDRootEntry VTDRootEntry; > #define VTD_CTX_ENTRY_LEGACY_SIZE 16 > #define VTD_CTX_ENTRY_SCALABLE_SIZE 32 > > +#define VTD_SM_CONTEXT_ENTRY_PDTS(val) (((val) >> 9) & 0x7) > #define VTD_SM_CONTEXT_ENTRY_RID2PASID_MASK 0xfffff > #define VTD_SM_CONTEXT_ENTRY_RSVD_VAL0(aw) (0x1e0ULL | ~VTD_HAW_MASK(aw)) > #define VTD_SM_CONTEXT_ENTRY_RSVD_VAL1 0xffffffffffe00000ULL > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > index 1db581d14a..f4273dc640 100644 > --- a/hw/i386/intel_iommu.c > +++ b/hw/i386/intel_iommu.c > @@ -826,6 +826,11 @@ static inline bool vtd_pe_type_check(IntelIOMMUState *s, VTDPASIDEntry *pe) > } > } > > +static inline uint32_t vtd_sm_ce_get_pdt_entry_num(VTDContextEntry *ce) > +{ > + return 1U << (VTD_SM_CONTEXT_ENTRY_PDTS(ce->val[0]) + 7); > +} > + > static inline uint16_t vtd_pe_get_did(VTDPASIDEntry *pe) > { > return VTD_SM_PASID_ENTRY_DID((pe)->val[1]); > @@ -3246,6 +3251,159 @@ remove: > return true; > } > > +static void vtd_sm_pasid_table_walk_one(IntelIOMMUState *s, > + dma_addr_t pt_base, > + int start, > + int end, > + VTDPASIDCacheInfo *info) > +{ > + VTDPASIDEntry pe; > + int pasid = start; > + int pasid_next; > + > + while (pasid < end) { > + pasid_next = pasid + 1; > + > + if (!vtd_get_pe_in_pasid_leaf_table(s, pasid, pt_base, &pe) > + && vtd_pe_present(&pe)) { > + int bus_n = pci_bus_num(info->bus), devfn = info->devfn; > + uint16_t sid = PCI_BUILD_BDF(bus_n, devfn); > + VTDAddressSpace *vtd_as; > + > + vtd_iommu_lock(s); > + /* > + * When indexed by rid2pasid, vtd_as should have been created, > + * e.g., by PCI subsystem. For other iommu pasid, we need to > + * create vtd_as dynamically. The other iommu pasid is same as > + * PCI's pasid, so it's used as input of vtd_find_add_as(). > + */ > + vtd_as = vtd_as_from_iommu_pasid_locked(s, sid, pasid); > + vtd_iommu_unlock(s); > + if (!vtd_as) { > + vtd_as = vtd_find_add_as(s, info->bus, devfn, pasid); > + } > + > + if ((info->type == VTD_PASID_CACHE_DOMSI || > + info->type == VTD_PASID_CACHE_PASIDSI) && > + !(info->domain_id == vtd_pe_get_did(&pe))) { > + /* > + * VTD_PASID_CACHE_DOMSI and VTD_PASID_CACHE_PASIDSI > + * requires domain ID check. If domain Id check fail, > + * go to next pasid. > + */ > + pasid = pasid_next; > + continue; > + } > + if (vtd_fill_pe_in_cache(s, vtd_as, &pe)) { > + pasid_cache_info_set_error(info); > + } > + } > + pasid = pasid_next; > + } > +} > + > +/* > + * Currently, VT-d scalable mode pasid table is a two level table, do you mean PASID dir + PASID table? in the positive I would use that terminology directly. > + * this function aims to loop a range of PASIDs in a given pasid aims at looping over a range of PASIDs in a given table? so what do you call a table here? is a a PASID directory ot a PASID table. > + * table to identify the pasid config in guest. > + */ > +static void vtd_sm_pasid_table_walk(IntelIOMMUState *s, > + dma_addr_t pdt_base, > + int start, > + int end, > + VTDPASIDCacheInfo *info) > +{ > + VTDPASIDDirEntry pdire; > + int pasid = start; > + int pasid_next; > + dma_addr_t pt_base; > + > + while (pasid < end) { > + pasid_next = ((end - pasid) > VTD_PASID_TBL_ENTRY_NUM) ? > + (pasid + VTD_PASID_TBL_ENTRY_NUM) : end; > + if (!vtd_get_pdire_from_pdir_table(pdt_base, pasid, &pdire) > + && vtd_pdire_present(&pdire)) { > + pt_base = pdire.val & VTD_PASID_TABLE_BASE_ADDR_MASK; > + vtd_sm_pasid_table_walk_one(s, pt_base, pasid, pasid_next, info); > + } > + pasid = pasid_next; > + } > +} > + > +static void vtd_replay_pasid_bind_for_dev(IntelIOMMUState *s, > + int start, int end, > + VTDPASIDCacheInfo *info) > +{ > + VTDContextEntry ce; > + > + if (!vtd_dev_to_context_entry(s, pci_bus_num(info->bus), info->devfn, > + &ce)) { > + uint32_t max_pasid; > + > + max_pasid = vtd_sm_ce_get_pdt_entry_num(&ce) * VTD_PASID_TBL_ENTRY_NUM; > + if (end > max_pasid) { > + end = max_pasid; > + } > + vtd_sm_pasid_table_walk(s, > + VTD_CE_GET_PASID_DIR_TABLE(&ce), > + start, > + end, > + info); > + } > +} > + > +/* > + * This function replay the guest pasid bindings to hosts by replays, host > + * walking the guest PASID table. This ensures host will have > + * latest guest pasid bindings. > + */ > +static void vtd_replay_guest_pasid_bindings(IntelIOMMUState *s, > + VTDPASIDCacheInfo *pc_info) > +{ > + VTDHostIOMMUDevice *vtd_hiod; > + int start = 0, end = 1; /* only rid2pasid is supported */ > + VTDPASIDCacheInfo walk_info; > + GHashTableIter as_it; > + > + switch (pc_info->type) { > + case VTD_PASID_CACHE_PASIDSI: > + start = pc_info->pasid; > + end = pc_info->pasid + 1; > + /* > + * PASID selective invalidation is within domain, > + * thus fall through. this is still not totally clean to me. For domsi I would have expected a different setting of start and end? > + */ > + case VTD_PASID_CACHE_DOMSI: fall though clause here and above? > + case VTD_PASID_CACHE_GLOBAL_INV: > + /* loop all assigned devices */ > + break; > + default: > + error_report("invalid pc_info->type for replay"); > + abort(); > + } > + > + /* > + * In this replay, only needs to care about the devices which one only needs to care > + * are backed by host IOMMU. For such devices, their vtd_hiod Those devices have a corresponding vtd_hiod in s->vtd_host_iommu_dev > + * instances are in the s->vtd_host_iommu_dev. For devices which > + * are not backed by host IOMMU, it is not necessary to replay > + * the bindings since their cache could be re-created in the future > + * DMA address translation. Access to vtd_host_iommu_dev is already > + * protected by BQL, so no iommu lock needed here. > + */ > + walk_info = *pc_info; > + g_hash_table_iter_init(&as_it, s->vtd_host_iommu_dev); > + while (g_hash_table_iter_next(&as_it, NULL, (void **)&vtd_hiod)) { > + /* bus|devfn fields are not identical with pc_info */ Can you clarify? > + walk_info.bus = vtd_hiod->bus; > + walk_info.devfn = vtd_hiod->devfn; > + vtd_replay_pasid_bind_for_dev(s, start, end, &walk_info); > + } > + if (walk_info.error_happened) { > + pasid_cache_info_set_error(pc_info); > + } > +} > + > /* > * This function syncs the pasid bindings between guest and host. > * It includes updating the pasid cache in vIOMMU and updating the > @@ -3301,7 +3459,16 @@ static void vtd_pasid_cache_sync(IntelIOMMUState *s, > pc_info); > vtd_iommu_unlock(s); > > - /* TODO: Step 2: loop all the existing vtd_hiod instances for pasid bind. */ > + /* > + * Step 2: loop all the existing vtd_hiod instances for pasid bind. > + * Ideally, needs to loop all devices to find if there is any new > + * PASID binding regards to the PASID cache invalidation request. > + * But it is enough to loop the devices which are backed by host > + * IOMMU. For devices backed by vIOMMU (a.k.a emulated devices), > + * if new PASID happened on them, their vtd_as instance could > + * be created during future vIOMMU DMA translation. the above comment is somehow redundant with the previous one > + */ > + vtd_replay_guest_pasid_bindings(s, pc_info); > } > > static bool vtd_process_pasid_desc(IntelIOMMUState *s, Thanks Eric