From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47062) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YxivT-00042s-Mt for qemu-devel@nongnu.org; Wed, 27 May 2015 17:31:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YxivS-0001xs-D6 for qemu-devel@nongnu.org; Wed, 27 May 2015 17:31:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57602) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YxivS-0001x9-53 for qemu-devel@nongnu.org; Wed, 27 May 2015 17:31:46 -0400 Message-ID: <1432762304.24271.91.camel@redhat.com> From: Alex Williamson Date: Wed, 27 May 2015 15:31:44 -0600 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC v8.1 03/13] vfio: add pcie extanded capability support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Chen Fan Cc: izumi.taku@jp.fujitsu.com, qemu-devel@nongnu.org On Wed, 2015-05-27 at 10:46 +0800, Chen Fan wrote: > For vfio pcie device, we could expose the extended capability on > PCIE bus. in order to avoid config space broken, we introduce > a copy config for parsing extended caps. and rebuild the pcie > extended config space. > > Signed-off-by: Chen Fan > --- > hw/vfio/pci.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 72 insertions(+), 1 deletion(-) > > diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c > index 78f4c82..81a4a9a 100644 > --- a/hw/vfio/pci.c > +++ b/hw/vfio/pci.c > @@ -2493,6 +2493,21 @@ static uint8_t vfio_std_cap_max_size(PCIDevice *pdev, uint8_t pos) > return next - pos; > } > > + > +static uint16_t vfio_ext_cap_max_size(const uint8_t *config, uint16_t pos) > +{ > + uint16_t tmp, next = PCIE_CONFIG_SPACE_SIZE - 1; > + > + for (tmp = PCI_CONFIG_SPACE_SIZE; tmp; > + tmp = PCI_EXT_CAP_NEXT(pci_get_long(config + tmp))) { > + if (tmp > pos && tmp < next) { > + next = tmp; > + } > + } > + > + return next - pos; > +} A bug in the existing vfio_std_cap_max_size() too, but shouldn't 'next' start at PCIE_CONFIG_SPACE_SIZE instead of PCIE_CONFIG_SPACE_SIZE-1? Capabilities need to be DWORD aligned, so say I have a capability starting 4 bytes from the end, 0xFFC. The max size should be 4 bytes, 0x1000 - 0xFFC, not 3 bytes, 0xFFF - 0xFFC. > + > static void vfio_set_word_bits(uint8_t *buf, uint16_t val, uint16_t mask) > { > pci_set_word(buf, (pci_get_word(buf) & ~mask) | val); > @@ -2802,16 +2817,72 @@ static int vfio_add_std_cap(VFIOPCIDevice *vdev, uint8_t pos) > return 0; > } > > +static int vfio_add_ext_cap(VFIOPCIDevice *vdev, const uint8_t *config) > +{ > + PCIDevice *pdev = &vdev->pdev; > + uint32_t header; > + uint16_t cap_id, next, size; > + uint8_t cap_ver; > + > + for (next = PCI_CONFIG_SPACE_SIZE; next; > + next = PCI_EXT_CAP_NEXT(pci_get_long(config + next))) { > + header = pci_get_long(config + next); > + cap_id = PCI_EXT_CAP_ID(header); > + cap_ver = PCI_EXT_CAP_VER(header); > + > + /* > + * If it becomes important to configure extended capabilities to their > + * actual size, use this as the default when it's something we don't > + * recognize. Since QEMU doesn't actually handle many of the config > + * accesses, exact size doesn't seem worthwhile. > + */ > + size = vfio_ext_cap_max_size(config, next); > + > + pcie_add_capability(pdev, cap_id, cap_ver, next, size); > + if (next == PCI_CONFIG_SPACE_SIZE) { > + /* Begin the rebuild, we should set the next offset zero. */ > + pci_set_long(pdev->config + next, PCI_EXT_CAP(cap_id, cap_ver, 0)); > + } > + > + /* Use emulated header pointer to allow dropping extended caps */ > + pci_set_long(vdev->emulated_config_bits + next, 0xffffffff); > + } > + > + return 0; > +} > + > static int vfio_add_capabilities(VFIOPCIDevice *vdev) > { > PCIDevice *pdev = &vdev->pdev; > + int ret; > + uint8_t *config; > > if (!(pdev->config[PCI_STATUS] & PCI_STATUS_CAP_LIST) || > !pdev->config[PCI_CAPABILITY_LIST]) { > return 0; /* Nothing to add */ > } > > - return vfio_add_std_cap(vdev, pdev->config[PCI_CAPABILITY_LIST]); > + ret = vfio_add_std_cap(vdev, pdev->config[PCI_CAPABILITY_LIST]); > + if (ret) { > + return ret; > + } > + > + /* on PCI bus, it doesn't make sense to expose extended capabilities. */ > + if (!pci_is_express(pdev) || > + !pci_bus_is_express(pdev->bus) || > + !pci_get_long(pdev->config + PCI_CONFIG_SPACE_SIZE)) { > + return 0; > + } > + > + /* > + * In order to avoid config space broken, here using a copy config to > + * parse extended capabilities. I think this should read something more like "In order to avoid breaking config space, create a copy to use for parsing extended capabilities". > + */ > + config = g_memdup(pdev->config, vdev->config_size); > + ret = vfio_add_ext_cap(vdev, config); > + > + g_free(config); > + return ret; > } > > static void vfio_pci_pre_reset(VFIOPCIDevice *vdev)