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[2003:cb:c71b:2c00:7bfb:29fe:9e6f:2e65]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-434f0a7e6e1sm86712525e9.36.2024.12.09.13.01.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Dec 2024 13:01:46 -0800 (PST) Message-ID: Date: Mon, 9 Dec 2024 22:01:44 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] s390x/pci: add support for guests that request direct mapping To: Matthew Rosato , qemu-s390x@nongnu.org Cc: farman@linux.ibm.com, schnelle@linux.ibm.com, thuth@redhat.com, pasic@linux.ibm.com, borntraeger@linux.ibm.com, richard.henderson@linaro.org, iii@linux.ibm.com, clegoate@redhat.com, qemu-devel@nongnu.org References: <20241209192927.107503-1-mjrosato@linux.ibm.com> <20241209192927.107503-2-mjrosato@linux.ibm.com> From: David Hildenbrand Content-Language: en-US Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <20241209192927.107503-2-mjrosato@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.489, 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_H2=-0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 09.12.24 20:29, Matthew Rosato wrote: > When receiving a guest mpcifc(4) or mpcifc(6) instruction without the T > bit set, treat this as a request to perform direct mapping instead of > address translation. In order to facilitiate this, pin the entirety of > guest memory into the host iommu. > > Subsequent guest DMA operations are all expected to be of the format > guest_phys+sdma, allowing them to be used as lookup into the host > iommu table. > > Signed-off-by: Matthew Rosato > --- > hw/s390x/s390-pci-bus.c | 23 ++++++++++++++++++ > hw/s390x/s390-pci-inst.c | 42 +++++++++++++++++++++++++++++++-- > include/hw/s390x/s390-pci-bus.h | 2 ++ > 3 files changed, 65 insertions(+), 2 deletions(-) > > diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c > index 40b2567aa7..8d4224e032 100644 > --- a/hw/s390x/s390-pci-bus.c > +++ b/hw/s390x/s390-pci-bus.c > @@ -18,6 +18,7 @@ > #include "hw/s390x/s390-pci-inst.h" > #include "hw/s390x/s390-pci-kvm.h" > #include "hw/s390x/s390-pci-vfio.h" > +#include "hw/boards.h" > #include "hw/pci/pci_bus.h" > #include "hw/qdev-properties.h" > #include "hw/pci/pci_bridge.h" > @@ -720,6 +721,27 @@ void s390_pci_iommu_enable(S390PCIIOMMU *iommu) > TYPE_S390_IOMMU_MEMORY_REGION, OBJECT(&iommu->mr), > name, iommu->pal + 1); > iommu->enabled = true; > + iommu->direct_map = false; > + memory_region_add_subregion(&iommu->mr, 0, MEMORY_REGION(&iommu->iommu_mr)); > + g_free(name); > +} > + > +void s390_pci_iommu_dm_enable(S390PCIIOMMU *iommu) > +{ > + MachineState *ms = MACHINE(qdev_get_machine()); > + > + /* > + * For direct-mapping we must map the entire guest address space. Because > + * the mappings are contiguous we are not restricted to individual 4K > + * mappings via vfio, so let's not worry about the DMA limit when > + * calculating the range. > + */ > + char *name = g_strdup_printf("iommu-s390-%04x", iommu->pbdev->uid); > + memory_region_init_iommu(&iommu->iommu_mr, sizeof(iommu->iommu_mr), > + TYPE_S390_IOMMU_MEMORY_REGION, OBJECT(&iommu->mr), > + name, iommu->pba + ms->ram_size); > + iommu->enabled = true; > + iommu->direct_map = true; > memory_region_add_subregion(&iommu->mr, 0, MEMORY_REGION(&iommu->iommu_mr)); > g_free(name); > } > @@ -727,6 +749,7 @@ void s390_pci_iommu_enable(S390PCIIOMMU *iommu) > void s390_pci_iommu_disable(S390PCIIOMMU *iommu) > { > iommu->enabled = false; > + iommu->direct_map = false; > g_hash_table_remove_all(iommu->iotlb); > memory_region_del_subregion(&iommu->mr, MEMORY_REGION(&iommu->iommu_mr)); > object_unparent(OBJECT(&iommu->iommu_mr)); > diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c > index 41655082da..f4d8fe8fe8 100644 > --- a/hw/s390x/s390-pci-inst.c > +++ b/hw/s390x/s390-pci-inst.c > @@ -16,6 +16,7 @@ > #include "exec/memory.h" > #include "qemu/error-report.h" > #include "sysemu/hw_accel.h" > +#include "hw/boards.h" > #include "hw/pci/pci_device.h" > #include "hw/s390x/s390-pci-inst.h" > #include "hw/s390x/s390-pci-bus.h" > @@ -990,6 +991,33 @@ int pci_dereg_irqs(S390PCIBusDevice *pbdev) > return 0; > } > > +static void s390_pci_setup_stage2_map(S390PCIIOMMU *iommu) > +{ > + MachineState *ms = MACHINE(qdev_get_machine()); > + uint64_t remain = ms->ram_size, start = iommu->pba, mask, size, curr = 0; > + uint64_t end = start + remain - 1; > + IOMMUTLBEvent event = { > + .type = IOMMU_NOTIFIER_MAP, > + .entry = { > + .target_as = &address_space_memory, > + .translated_addr = 0, > + .perm = IOMMU_RW, > + }, > + }; > + > + while (remain >= TARGET_PAGE_SIZE) { > + mask = dma_aligned_pow2_mask(start, end, 64); > + size = mask + 1; > + event.entry.iova = start; > + event.entry.addr_mask = mask; > + event.entry.translated_addr = curr; > + memory_region_notify_iommu(&iommu->iommu_mr, 0, event); > + start += size; > + curr += size; > + remain -= size; > + } > +} Hi, Trying to wrap my head around that ... you mention that "pin the entirety of guest memory". Do you mean that we will actually end up longterm pinning all guest RAM in the kernel, similar to what vfio ends up doing? In that case, it would be incompatible with virtio-balloon (and without modifications with upcoming virtio-mem). Is there already a mechanism in place to handle that -- a call to ram_block_discard_disable() -- or even a way to support coordinated discarding of RAM (e.g., virtio-mem + vfio)? -- Cheers, David / dhildenb