From 7faf90ef995ea470f32f43810266ece8ac8ba6c7 Mon Sep 17 00:00:00 2001 From: Paul Bolle Date: Thu, 3 Mar 2016 13:01:40 +0100 Subject: [PATCH] lguest: Read length of device_cap later Read the length of the capability with type VIRTIO_PCI_CAP_DEVICE_CFG only when we're sure we're going to need it. Which is just before the check whether the virtio console actually has an emerg_wr field. Signed-off-by: Paul Bolle Cc: Rusty Russell Cc: lguest@lists.ozlabs.org Link: http://lkml.kernel.org/r/1457006501-5377-2-git-send-email-pebolle@tiscali.nl Signed-off-by: Thomas Gleixner --- arch/x86/lguest/boot.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 3847e736702e..146d11c8cf78 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -1258,7 +1258,7 @@ static void probe_pci_console(void) u8 vndr = read_pci_config_byte(0, 1, 0, cap); if (vndr == PCI_CAP_ID_VNDR) { u8 type, bar; - u32 offset, length; + u32 offset; type = read_pci_config_byte(0, 1, 0, cap + offsetof(struct virtio_pci_cap, cfg_type)); @@ -1266,15 +1266,12 @@ static void probe_pci_console(void) cap + offsetof(struct virtio_pci_cap, bar)); offset = read_pci_config(0, 1, 0, cap + offsetof(struct virtio_pci_cap, offset)); - length = read_pci_config(0, 1, 0, - cap + offsetof(struct virtio_pci_cap, length)); switch (type) { case VIRTIO_PCI_CAP_DEVICE_CFG: if (bar == 0) { device_cap = cap; device_offset = offset; - device_len = length; } break; case VIRTIO_PCI_CAP_PCI_CFG: @@ -1297,6 +1294,8 @@ static void probe_pci_console(void) * emerg_wr. If it doesn't support VIRTIO_CONSOLE_F_EMERG_WRITE * it should ignore the access. */ + device_len = read_pci_config(0, 1, 0, + device_cap + offsetof(struct virtio_pci_cap, length)); if (device_len < (offsetof(struct virtio_console_config, emerg_wr) + sizeof(u32))) { printk(KERN_ERR "lguest: console missing emerg_wr field\n"); -- 2.20.1