From d8cc073c06a4c79e24a86a958b8c1ac7a26fa039 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Fri, 10 Apr 2015 16:33:45 +0200 Subject: [PATCH 02/14] vfio: Do not reattempt a failed rom read Message-id: <20150410163345.15324.23733.stgit@gimli.home> Patchwork-id: 64790 O-Subject: [RHEL7.2 qemu-kvm PATCH 2/8] vfio: Do not reattempt a failed rom read Bugzilla: 1210503 RH-Acked-by: Thomas Huth RH-Acked-by: Laszlo Ersek RH-Acked-by: Bandan Das From: Bandan Das Upstream: e638073c569e801ce9def2016a84f955cbbca779 During lazy rom loading, if rom read fails, and the guest attempts a read again, vfio will again attempt it. Add a boolean to prevent this. There could be a case where a failed rom read might succeed the next time because of a device reset or such, but it's best to exclude unpredictable behavior Signed-off-by: Bandan Das Signed-off-by: Alex Williamson Signed-off-by: Miroslav Rezanina --- hw/misc/vfio.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c index c9dbc28..f3bf491 100644 --- a/hw/misc/vfio.c +++ b/hw/misc/vfio.c @@ -206,6 +206,7 @@ typedef struct VFIODevice { bool has_flr; bool has_pm_reset; bool needs_reset; + bool rom_read_failed; } VFIODevice; typedef struct VFIOGroup { @@ -1197,6 +1198,7 @@ static void vfio_pci_load_rom(VFIODevice *vdev) vdev->rom_offset = reg_info.offset; if (!vdev->rom_size) { + vdev->rom_read_failed = true; error_report("vfio-pci: Cannot read device rom at " "%04x:%02x:%02x.%x\n", vdev->host.domain, vdev->host.bus, vdev->host.slot, @@ -1235,6 +1237,9 @@ static uint64_t vfio_rom_read(void *opaque, hwaddr addr, unsigned size) /* Load the ROM lazily when the guest tries to read it */ if (unlikely(!vdev->rom)) { vfio_pci_load_rom(vdev); + if (unlikely(!vdev->rom && !vdev->rom_read_failed)) { + vfio_pci_load_rom(vdev); + } } memcpy(&val, vdev->rom + addr, @@ -1352,6 +1357,7 @@ static void vfio_pci_size_rom(VFIODevice *vdev) PCI_BASE_ADDRESS_SPACE_MEMORY, &vdev->pdev.rom); vdev->pdev.has_rom = true; + vdev->rom_read_failed = false; } static void vfio_vga_write(void *opaque, hwaddr addr, -- 1.8.3.1