From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59254) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dmbRq-0006Bv-MV for qemu-devel@nongnu.org; Tue, 29 Aug 2017 04:00:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dmbRm-0001TV-K4 for qemu-devel@nongnu.org; Tue, 29 Aug 2017 04:00:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47360) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dmbRm-0001Rg-EN for qemu-devel@nongnu.org; Tue, 29 Aug 2017 04:00:30 -0400 Date: Tue, 29 Aug 2017 10:00:25 +0200 From: Cornelia Huck Message-ID: <20170829100025.639b0ebb.cohuck@redhat.com> In-Reply-To: References: <1503907487-2764-1-git-send-email-zyimin@linux.vnet.ibm.com> <1503907487-2764-2-git-send-email-zyimin@linux.vnet.ibm.com> <20170828165122.041b62b2.cohuck@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH 1/4] s390x/pci: fixup trap_msix() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Yi Min Zhao Cc: qemu-devel@nongnu.org, borntraeger@de.ibm.com, pasic@linux.vnet.ibm.com, pmorel@linux.vnet.ibm.com, agraf@suse.de, richard.henderson@linaro.org On Tue, 29 Aug 2017 12:32:17 +0800 Yi Min Zhao wrote: > =E5=9C=A8 2017/8/28 =E4=B8=8B=E5=8D=8810:51, Cornelia Huck =E5=86=99=E9= =81=93: > > On Mon, 28 Aug 2017 10:04:44 +0200 > > Yi Min Zhao wrote: > > =20 > >> The function trap_msix() is to check if pcistg instruction would access > >> msix table entries. The correct boundary condition should be > >> [table_offset, table_offset+entries*entry_size). But the current > >> condition calculated misses the last entry. So let's fixup it. > >> > >> Acked-by: Dong Jia Shi > >> Reviewed-by: Pierre Morel > >> Signed-off-by: Yi Min Zhao > >> --- > >> hw/s390x/s390-pci-inst.c | 4 ++-- > >> 1 file changed, 2 insertions(+), 2 deletions(-) > >> > >> diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c > >> index b7beb8c36a..eba9ffb5f2 100644 > >> --- a/hw/s390x/s390-pci-inst.c > >> +++ b/hw/s390x/s390-pci-inst.c > >> @@ -440,8 +440,8 @@ static int trap_msix(S390PCIBusDevice *pbdev, uint= 64_t offset, uint8_t pcias) > >> { > >> if (pbdev->msix.available && pbdev->msix.table_bar =3D=3D pcias = && > >> offset >=3D pbdev->msix.table_offset && > >> - offset <=3D pbdev->msix.table_offset + > >> - (pbdev->msix.entries - 1) * PCI_MSIX_ENTRY_SIZE) { > >> + offset < (pbdev->msix.table_offset + > >> + pbdev->msix.entries * PCI_MSIX_ENTRY_SIZE)) { > >> return 1; > >> } else { > >> return 0; =20 > > What happened before due to the miscalculation? Write to wrong memory > > region? > > > > =20 > We tried to plug virtio-net pci device but failed. After inspected, we > found that the device uses two msix entries but the last one was > missed. Then we cannot register interrupt successfully because we > should call trap_msixi() in order to save some useful and arch > information into msix message. But what about wrong memory region > didn't happen. So, the guest just was not able to use the second msix entry, but did not get any exception?