From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:41275) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T7TET-0004u1-If for qemu-devel@nongnu.org; Fri, 31 Aug 2012 11:34:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T7TEL-0008H3-92 for qemu-devel@nongnu.org; Fri, 31 Aug 2012 11:34:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22998) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T7TEL-0008Gf-0d for qemu-devel@nongnu.org; Fri, 31 Aug 2012 11:33:57 -0400 Date: Fri, 31 Aug 2012 18:35:13 +0300 From: "Michael S. Tsirkin" Message-ID: <20120831153513.GB24891@redhat.com> References: <20120831084227.GA24072@redhat.com> <20120831144551.GB12212@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120831144551.GB12212@redhat.com> Subject: Re: [Qemu-devel] [PATCH 2/2] pcie_aer: clear cmask for Advanced Error Interrupt Message Number List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Baron Cc: yamahata@valinux.co.jp, alex.williamson@redhat.com, jan.kiszka@siemens.com, qemu-devel@nongnu.org, quintela@redhat.com On Fri, Aug 31, 2012 at 10:45:52AM -0400, Jason Baron wrote: > On Fri, Aug 31, 2012 at 11:42:27AM +0300, Michael S. Tsirkin wrote: > > Some minor nits below. If you dont get to it I will tweak this patch > > when I apply it early next week. > > > > On Thu, Aug 30, 2012 at 01:51:15PM -0400, Jason Baron wrote: > > > The Advanced Error Interrupt Message Number (bits 31:27 of the Root > > > Error Status Register) is updated when the number of msi messages assigned to a > > > device changes. Migration of windows 7 on q35 chipset failed because the check > > > in get_pci_config_device() fails due to wmask being set on these bits. > > > > I think you actually mean 'not being set on these bits'? > > > > No, the check is: > > static int get_pci_config_device(QEMUFile *f, void *pv, size_t size) > { > PCIDevice *s = container_of(pv, PCIDevice, config); > uint8_t *config; > int i; > > assert(size == pci_config_size(s)); > config = g_malloc(size); > > qemu_get_buffer(f, config, size); > for (i = 0; i < size; ++i) { > if ((config[i] ^ s->config[i]) & > s->cmask[i] & ~s->wmask[i] & ~s->w1cmask[i]) { > g_free(config); > return -EINVAL; > } > } > ..... > > So because cmask is set and these bits differ in config space (due to > them being updated before migration), the migration aborts. Ah so you mean 'cmask being set' - not wmask as you wrote. > > > > Its valid > > > to update these bits and we must restore this state across migration. > > > > > > Signed-off-by: Jason Baron > > > --- > > > hw/pcie_aer.c | 6 ++++++ > > > 1 files changed, 6 insertions(+), 0 deletions(-) > > > > > > diff --git a/hw/pcie_aer.c b/hw/pcie_aer.c > > > index 3b6981c..6edcd79 100644 > > > --- a/hw/pcie_aer.c > > > +++ b/hw/pcie_aer.c > > > @@ -738,6 +738,12 @@ void pcie_aer_root_init(PCIDevice *dev) > > > PCI_ERR_ROOT_CMD_EN_MASK); > > > pci_set_long(dev->w1cmask + pos + PCI_ERR_ROOT_STATUS, > > > PCI_ERR_ROOT_STATUS_REPORT_MASK); > > > + /* Bits 31:27 - Advanced Error Interrupt Message Number > > > > This line is better moved to near definition of PCI_ERR_ROOT_IRQ. > > Then here we can say 'PCI_ERR_ROOT_IRQ is RO but devices > > change it using a device-specific method.' > > ok. > > > > > > + * These bits are updated when the number of MSI messages changes. > > > + * By clearing the cmask, pcie devices can be migrated. > > > + */ > > > + pci_set_long(dev->cmask + pos + PCI_ERR_ROOT_STATUS, > > > + (1 << PCI_ERR_ROOT_IRQ_SHIFT) - 1); > > > > ~PCI_ERR_ROOT_IRQ would be clearer I think. > > > > agreed. > > I will re-spin and post a v2. > > Thanks, > > -Jason