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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=pbonzini@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_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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 4/15/25 13:55, Philippe Mathieu-Daudé wrote: > On 15/4/25 13:51, Paolo Bonzini wrote: >> On Tue, Apr 15, 2025 at 1:51 PM CLEMENT MATHIEU--DRIF >> wrote: >>> On 15/04/2025 11:30 am, Paolo Bonzini wrote: >>>> Caution: External email. Do not open attachments or click links, unless >>>> this email comes from a known sender and you know the content is safe. >>>> >>>> >>>> On 4/15/25 08:18, CLEMENT MATHIEU--DRIF wrote: >>>>> Address space creation might end up being called without holding the >>>>> bql as it is exposed through the IOMMU ops. >>>>> >>>>> Signed-off-by: Clement Mathieu--Drif >>>> drif@eviden.com> >>>> >>>> Please use a separate lock instead of the BQL. >>> >>> Hi Paolo, >>> >>> We need this particular lock because some of the functions we call >>> require the bql to be held. >> >> What functions do you need? >> >>> Is it a problem? >> >> It depends on the function. :) > > memory_region_set_enabled() >   -> memory_region_transaction_begin() >      -> assert(bql_locked()) Oh, I found Yi Liu's reply that came a little before mine. Yeah, then I guess this is unavoidable (short of adding locks to all of memory.c---which would be a good thing but...). But please mention this in the comment that you are adding; this: /* Some functions in this branch require the bql, make sure we own it */ describes the code but does not explain it. Paolo