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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <17e3595f-6d12-0dc1-2623-d85163c98d3b@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=thuth@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=thuth@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/11/17 01:18:45 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alex Williamson , Pierre Morel , David Hildenbrand , Richard Henderson , qemu-devel@nongnu.org, Halil Pasic , Christian Borntraeger , qemu-s390x@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 17/11/2020 19.49, Philippe Mathieu-Daudé wrote: > On 11/17/20 7:39 PM, Thomas Huth wrote: >> On 17/11/2020 19.30, Philippe Mathieu-Daudé wrote: >>> On 11/17/20 7:19 PM, Matthew Rosato wrote: >>>> On 11/17/20 12:59 PM, Philippe Mathieu-Daudé wrote: >>>>> On 11/17/20 6:13 PM, Cornelia Huck wrote: >>>>>> zPCI control blocks are big endian, we need to take care that we >>>>>> do proper accesses in order not to break tcg guests on little endian >>>>>> hosts. >>>>>> >>>>>> Fixes: 28dc86a07299 ("s390x/pci: use a PCI Group structure") >>>>>> Fixes: 9670ee752727 ("s390x/pci: use a PCI Function structure") >>>>>> Fixes: 1e7552ff5c34 ("s390x/pci: get zPCI function info from host") >>>>>> Signed-off-by: Cornelia Huck >>>>>> --- >>>>>> >>>>>> Works for me with virtio-pci devices for tcg on x86 and s390x, and >>>>>> for kvm. >>>>>> The vfio changes are not strictly needed; did not test them due to >>>>>> lack of >>>>>> hardware -- testing appreciated. >> >>>>>> As this fixes a regression, I want this in 5.2. >>>>>> >>>>>> --- >>>>>>   hw/s390x/s390-pci-bus.c  | 12 ++++++------ >>>>>>   hw/s390x/s390-pci-inst.c |  4 ++-- >>>>>>   hw/s390x/s390-pci-vfio.c |  8 ++++---- >>>>>>   3 files changed, 12 insertions(+), 12 deletions(-) >>>>>> >>>>>> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c >>>>>> index e0dc20ce4a56..17e64e0b1200 100644 >>>>>> --- a/hw/s390x/s390-pci-bus.c >>>>>> +++ b/hw/s390x/s390-pci-bus.c >>>>>> @@ -787,12 +787,12 @@ static void s390_pci_init_default_group(void) >>>>>>     static void set_pbdev_info(S390PCIBusDevice *pbdev) >>>>>>   { >>>>>> -    pbdev->zpci_fn.sdma = ZPCI_SDMA_ADDR; >>>>>> -    pbdev->zpci_fn.edma = ZPCI_EDMA_ADDR; >>>>>> -    pbdev->zpci_fn.pchid = 0; >>>>>> +    stq_p(&pbdev->zpci_fn.sdma, ZPCI_SDMA_ADDR); >>>>> >>>>> "zPCI control blocks are big endian" so don't we >>>>> need the _be_ accessors? stq_be_p() etc... >>>>> >>>> >>>> I don't think this is necessary.  This is only available for target >>>> s390x, which is always big endian...  cpu-all.h should define stq_p as >>>> stq_be_p for example inside the #if defined(TARGET_WORDS_BIGENDIAN). >>> >>> But if you run on little-endian host, you need to byte-swap that, >>> isn't it? >> >> It's done by the macros. They depend on the target endianess. See cpu-all.h. > > I'm confused because the description is about target endianness, > but stq_p() is about host alignment. stq_p() is apparently also about endianess. Why would it depend on TARGET_WORDS_BIGENDIAN otherwise? Thomas