From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33220) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WYHCU-0005Pq-9M for qemu-devel@nongnu.org; Thu, 10 Apr 2014 11:47:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WYHCO-00025c-4c for qemu-devel@nongnu.org; Thu, 10 Apr 2014 11:47:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52921) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WYHCN-00025V-Sg for qemu-devel@nongnu.org; Thu, 10 Apr 2014 11:47:32 -0400 Date: Thu, 10 Apr 2014 18:48:12 +0300 From: "Michael S. Tsirkin" Message-ID: <20140410154812.GH21110@redhat.com> References: <1397136581-10500-1-git-send-email-marcel.a@redhat.com> <1397136581-10500-2-git-send-email-marcel.a@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1397136581-10500-2-git-send-email-marcel.a@redhat.com> Subject: Re: [Qemu-devel] [PATCH V3 1/2] hw/pci: reserve IO and mem for pci-2-pci bridges with no devices attached List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Marcel Apfelbaum Cc: kevin@koconnor.net, seabios@seabios.org, qemu-devel@nongnu.org, kraxel@redhat.com On Thu, Apr 10, 2014 at 04:29:40PM +0300, Marcel Apfelbaum wrote: > If a pci-2-pci bridge supports hot-plug functionality but there are no devices > connected to it, reserve IO/mem in order to be able to attach devices > later. Do not waste space, use minimum allowed. > > Signed-off-by: Marcel Apfelbaum Looks good to me Reviewed-by: Michael S. Tsirkin but let's apply with patch 2 (after it's fixed): otherwise there's no way for hypervisors to avoid wasting resources unnecessaily on bridges. > --- > src/fw/pciinit.c | 3 +++ > src/hw/pci.c | 19 +++++++++++++++++++ > src/hw/pci.h | 1 + > 3 files changed, 23 insertions(+) > > diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c > index 64f1d41..9b5d7ad 100644 > --- a/src/fw/pciinit.c > +++ b/src/fw/pciinit.c > @@ -677,12 +677,15 @@ static int pci_bios_check_devices(struct pci_bus *busses) > continue; > struct pci_bus *parent = &busses[pci_bdf_to_bus(s->bus_dev->bdf)]; > int type; > + u8 shpc_cap = pci_find_capability(s->bus_dev, PCI_CAP_ID_SHPC); > for (type = 0; type < PCI_REGION_TYPE_COUNT; type++) { > u64 align = (type == PCI_REGION_TYPE_IO) ? > PCI_BRIDGE_IO_MIN : PCI_BRIDGE_MEM_MIN; > if (pci_region_align(&s->r[type]) > align) > align = pci_region_align(&s->r[type]); > u64 sum = pci_region_sum(&s->r[type]); > + if (!sum && shpc_cap) > + sum = align; /* reserve min size for hot-plug */ > u64 size = ALIGN(sum, align); > int is64 = pci_bios_bridge_region_is64(&s->r[type], > s->bus_dev, type); > diff --git a/src/hw/pci.c b/src/hw/pci.c > index caf9265..055353d 100644 > --- a/src/hw/pci.c > +++ b/src/hw/pci.c > @@ -225,6 +225,25 @@ pci_find_init_device(const struct pci_device_id *ids, void *arg) > return NULL; > } > > +u8 pci_find_capability(struct pci_device *pci, u8 cap_id) > +{ > + int i; > + u8 cap; > + u16 status = pci_config_readw(pci->bdf, PCI_STATUS); > + > + if (!(status & PCI_STATUS_CAP_LIST)) > + return 0; > + > + for (i = 0, cap = pci_config_readb(pci->bdf, PCI_CAPABILITY_LIST); > + (i <= 0xff) && cap; > + i++, cap = pci_config_readb(pci->bdf, cap + PCI_CAP_LIST_NEXT)) > + if (pci_config_readb(pci->bdf, cap + PCI_CAP_LIST_ID) == cap_id) > + return cap; > + > + return 0; > +} > + > + > void > pci_reboot(void) > { > diff --git a/src/hw/pci.h b/src/hw/pci.h > index 167a027..e828225 100644 > --- a/src/hw/pci.h > +++ b/src/hw/pci.h > @@ -116,6 +116,7 @@ int pci_init_device(const struct pci_device_id *ids > , struct pci_device *pci, void *arg); > struct pci_device *pci_find_init_device(const struct pci_device_id *ids > , void *arg); > +u8 pci_find_capability(struct pci_device *pci, u8 cap_id); > void pci_reboot(void); > > #endif > -- > 1.8.3.1