From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53026) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eS1Q8-00062j-Qc for qemu-devel@nongnu.org; Thu, 21 Dec 2017 09:02:08 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eS1Q3-0000NV-6F for qemu-devel@nongnu.org; Thu, 21 Dec 2017 09:02:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54318) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eS1Q2-0000N5-Tk for qemu-devel@nongnu.org; Thu, 21 Dec 2017 09:01:55 -0500 Date: Thu, 21 Dec 2017 16:01:46 +0200 From: "Michael S. Tsirkin" Message-ID: <20171221155923-mutt-send-email-mst@kernel.org> References: <20171208063113.20383-1-lprosek@redhat.com> <545999678.39861203.1512742146072.JavaMail.zimbra@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <545999678.39861203.1512742146072.JavaMail.zimbra@redhat.com> 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: Marcel Apfelbaum Cc: Ladi Prosek , qemu-devel@nongnu.org, geoff@hostfission.com, alex williamson 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? -- MST