From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45439) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eS2T8-0000da-M7 for qemu-devel@nongnu.org; Thu, 21 Dec 2017 10:09:16 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eS2T4-0006vY-3u for qemu-devel@nongnu.org; Thu, 21 Dec 2017 10:09:10 -0500 Received: from mx1.redhat.com ([209.132.183.28]:35088) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eS2T3-0006r5-R4 for qemu-devel@nongnu.org; Thu, 21 Dec 2017 10:09:06 -0500 References: <20171208063113.20383-1-lprosek@redhat.com> <545999678.39861203.1512742146072.JavaMail.zimbra@redhat.com> <20171221155923-mutt-send-email-mst@kernel.org> From: Marcel Apfelbaum Message-ID: <200a2a4e-e238-e427-d683-2e028ddeb167@redhat.com> Date: Thu, 21 Dec 2017 17:08:58 +0200 MIME-Version: 1.0 In-Reply-To: <20171221155923-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2] msix: don't mask already masked vectors on reset List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Ladi Prosek , qemu-devel@nongnu.org, geoff@hostfission.com, alex williamson On 21/12/2017 16:01, Michael S. Tsirkin wrote: > On Fri, Dec 08, 2017 at 09:09:06AM -0500, Marcel Apfelbaum wrote: >> >> >> ----- Original Message ----- >>> From: "Ladi Prosek" >>> To: qemu-devel@nongnu.org >>> Cc: marcel@redhat.com, geoff@hostfission.com, mst@redhat.com, "alex williamson" >>> Sent: Friday, December 8, 2017 8:31:13 AM >>> Subject: [PATCH v2] msix: don't mask already masked vectors on reset >>> >>> msix_mask_all() is supposed to invoke the release vector notifier if the >>> state of the >>> respective vector changed from unmasked to masked. The way it's currently >>> called from >>> msix_reset(), though, may result in calling the release notifier even if the >>> vector >>> is already masked. >>> >>> 1) msix_reset() clears out the msix_cap field and the msix_table. >>> 2) msix_mask_all() runs with was_masked=false for all vectors because of 1), >>> which >>> results in calling the release notifier on all vectors. >>> 3) if msix_reset() is subsequently called again, it goes through the same >>> steps and >>> calls the release notifier on all vectors again. >>> >>> This commit moves msix_mask_all() up so it runs before the device state is >>> lost. And >>> it adds an assignment to msix_function_masked so that the device remembers >>> that >>> MSI-X is masked. >>> >>> This is likely a low impact issue, found while debugging an already broken >>> device. It >>> is however easy to fix and the expectation that the use and release notifier >>> invocations >>> are always balanced is very natural. >>> >>> Signed-off-by: Ladi Prosek >>> --- >>> >>> v1->v2: >>> * fixed typo in commit message "or" -> "to" (Marcel) >>> * directly set msix_function_masked to true instead of calling >>> msix_update_function_masked() (Marcel) >>> >>> >>> hw/pci/msix.c | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/hw/pci/msix.c b/hw/pci/msix.c >>> index c944c02135..d6a4dbdb6b 100644 >>> --- a/hw/pci/msix.c >>> +++ b/hw/pci/msix.c >>> @@ -500,11 +500,12 @@ void msix_reset(PCIDevice *dev) >>> return; >>> } >>> msix_clear_all_vectors(dev); >>> + msix_mask_all(dev, dev->msix_entries_nr); >>> dev->config[dev->msix_cap + MSIX_CONTROL_OFFSET] &= >>> ~dev->wmask[dev->msix_cap + MSIX_CONTROL_OFFSET]; >>> memset(dev->msix_table, 0, dev->msix_entries_nr * PCI_MSIX_ENTRY_SIZE); >>> memset(dev->msix_pba, 0, QEMU_ALIGN_UP(dev->msix_entries_nr, 64) / 8); >>> - msix_mask_all(dev, dev->msix_entries_nr); >>> + dev->msix_function_masked = true; >>> } >>> >>> /* PCI spec suggests that devices make it possible for software to configure >>> -- >>> 2.13.6 >>> >>> >> >> Thanks Ladi! >> >> Reviewed-by: Marcel Apfelbaum > > This breaks make check though. > > Marcel - could you take a look please? > Sure Thanks, Marcel