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([2a01:e0a:f0e:9070:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-45b6f2f31d2sm34890185e9.25.2025.08.27.09.22.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 27 Aug 2025 09:22:13 -0700 (PDT) Message-ID: <5b25de4b-ae84-4926-9e14-2ab4262e973f@redhat.com> Date: Wed, 27 Aug 2025 18:22:12 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 12/21] intel_iommu: Handle PASID entry addition 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, 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 References: <20250822064101.123526-1-zhenzhong.duan@intel.com> <20250822064101.123526-13-zhenzhong.duan@intel.com> From: Eric Auger In-Reply-To: <20250822064101.123526-13-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_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-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 8/22/25 8:40 AM, Zhenzhong Duan wrote: > When guest creates new PASID entries, QEMU will capture the guest pasid > selective pasid cache invalidation, walk through each passthrough device > and each pasid, when a match is found, identify an existing vtd_as or > create a new one and update its corresponding cached pasid entry. You need to emphasize that the support is currently limited to Requests-without-PASID > > Signed-off-by: Yi Liu > Signed-off-by: Yi Sun > Signed-off-by: Zhenzhong Duan > --- > hw/i386/intel_iommu_internal.h | 2 + > hw/i386/intel_iommu.c | 176 ++++++++++++++++++++++++++++++++- > 2 files changed, 175 insertions(+), 3 deletions(-) > > diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h > index b9b76dd996..fb2a919e87 100644 > --- a/hw/i386/intel_iommu_internal.h > +++ b/hw/i386/intel_iommu_internal.h > @@ -559,6 +559,7 @@ typedef struct VTDRootEntry VTDRootEntry; > #define VTD_CTX_ENTRY_LEGACY_SIZE 16 > #define VTD_CTX_ENTRY_SCALABLE_SIZE 32 > > +#define VTD_SM_CONTEXT_ENTRY_PDTS(x) extract64((x)->val[0], 9, 3) > #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 > @@ -589,6 +590,7 @@ typedef struct VTDPASIDCacheInfo { > #define VTD_PASID_TABLE_BITS_MASK (0x3fULL) > #define VTD_PASID_TABLE_INDEX(pasid) ((pasid) & VTD_PASID_TABLE_BITS_MASK) > #define VTD_PASID_ENTRY_FPD (1ULL << 1) /* Fault Processing Disable */ > +#define VTD_PASID_TBL_ENTRY_NUM (1ULL << 6) > > /* PASID Granular Translation Type Mask */ > #define VTD_PASID_ENTRY_P 1ULL > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > index a2ee6d684e..7d2c9feae7 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) + 7); > +} > + > static inline bool vtd_pdire_present(VTDPASIDDirEntry *pdire) > { > return pdire->val & 1; > @@ -1647,9 +1652,9 @@ static gboolean vtd_find_as_by_sid_and_iommu_pasid(gpointer key, gpointer value, > } > > /* Translate iommu pasid to vtd_as */ > -static inline > -VTDAddressSpace *vtd_as_from_iommu_pasid_locked(IntelIOMMUState *s, > - uint16_t sid, uint32_t pasid) > +static VTDAddressSpace *vtd_as_from_iommu_pasid_locked(IntelIOMMUState *s, > + uint16_t sid, > + uint32_t pasid) > { > struct vtd_as_raw_key key = { > .sid = sid, > @@ -3220,10 +3225,172 @@ remove: > return true; > } > > +/* > + * This function walks over PASID range within [start, end) in a single > + * PASID table for entries matching @info type/did, then retrieve/create > + * vtd_as and fill associated pasid entry cache. > + */ > +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; > + > + while (pasid < end) { > + 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); > + VTDPASIDCacheEntry *pc_entry; > + 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. Other iommu pasid is same value since you don't support somthing else than rid2pasid, I would drop that and simplify the code. See below. > + * 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); you could check the vtd_as already exists here per the rid2pasid support limitation > + } > + > + if ((info->type == VTD_PASID_CACHE_DOMSI || > + info->type == VTD_PASID_CACHE_PASIDSI) && > + (info->did != VTD_SM_PASID_ENTRY_DID(&pe))) { > + /* > + * VTD_PASID_CACHE_DOMSI and VTD_PASID_CACHE_PASIDSI > + * requires domain id check. If domain id check fail, fails > + * go to next pasid. > + */ > + pasid++; > + continue; > + } > + > + pc_entry = &vtd_as->pasid_cache_entry; > + /* > + * pasid cache update and clear are handled in > + * vtd_flush_pasid_locked(), only care new pasid entry here. > + */ > + if (!pc_entry->valid) { > + pc_entry->pasid_entry = pe; > + pc_entry->valid = true; > + } > + } > + pasid++; > + } > +} > + > +/* > + * In VT-d scalable mode translation, PASID dir + PASID table is used. > + * This function aims at looping over a range of PASIDs in the given > + * two level 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 = > + (pasid + VTD_PASID_TBL_ENTRY_NUM) & ~(VTD_PASID_TBL_ENTRY_NUM - 1); > + pasid_next = pasid_next < end ? pasid_next : 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 replays the guest pasid bindings by walking the two level > + * guest PASID table. For each valid pasid entry, it finds or creates a > + * vtd_as and caches pasid entry in vtd_as. > + */ > +static void vtd_replay_guest_pasid_bindings(IntelIOMMUState *s, > + VTDPASIDCacheInfo *pc_info) > +{ > + /* > + * Currently only Requests-without-PASID is supported, as vIOMMU doesn't > + * support RPS(RID-PASID Support), pasid scope is fixed to [0, 1). > + */ > + int start = 0, end = 1; > + VTDHostIOMMUDevice *vtd_hiod; > + VTDPASIDCacheInfo walk_info; > + GHashTableIter as_it; > + > + switch (pc_info->type) { > + case VTD_PASID_CACHE_PASIDSI: > + start = pc_info->pasid; > + end = pc_info->pasid + 1; if you never replay a range, you could simplify the code for now because some code paths are not properly tested > + /* fall through */ > + case VTD_PASID_CACHE_DOMSI: Why can't we have other invalidation types along with request without PASID? It is not obvious to me at least why it couldn't be used by the guest. Would deserve a comment in the commit desc I think. > + case VTD_PASID_CACHE_GLOBAL_INV: > + /* loop all assigned devices */ > + break; > + default: > + error_setg(&error_fatal, "invalid pc_info->type for replay"); > + } > + > + /* > + * In this replay, one only needs to care about the devices which are > + * backed by host IOMMU. Those devices have a corresponding vtd_hiod > + * in s->vtd_host_iommu_dev. For devices 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. > + * > + * VTD translation callback never accesses vtd_hiod and its corresponding > + * cached pasid entry, 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)) { > + walk_info.bus = vtd_hiod->bus; > + walk_info.devfn = vtd_hiod->devfn; > + vtd_replay_pasid_bind_for_dev(s, start, end, &walk_info); > + } > +} > + > /* > * For a PASID cache invalidation, this function handles below scenarios: > * a) a present cached pasid entry needs to be removed > * b) a present cached pasid entry needs to be updated > + * c) a present cached pasid entry needs to be created > */ > static void vtd_pasid_cache_sync(IntelIOMMUState *s, VTDPASIDCacheInfo *pc_info) > { > @@ -3239,6 +3406,9 @@ static void vtd_pasid_cache_sync(IntelIOMMUState *s, VTDPASIDCacheInfo *pc_info) > g_hash_table_foreach_remove(s->vtd_address_spaces, vtd_flush_pasid_locked, > pc_info); > vtd_iommu_unlock(s); > + > + /* c): loop all passthrough device for new pasid entries */ > + vtd_replay_guest_pasid_bindings(s, pc_info); > } > > static bool vtd_process_pasid_desc(IntelIOMMUState *s, Thanks Eric