From 8eb85fb5ac60bfb6ee4c729cc087078d490670c4 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Mon, 22 May 2023 23:17:40 +0300 Subject: [PATCH] pci: ROM preallocation for incoming migration MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit On incoming migration we have the following sequence to load option ROM: 1. On device realize we do normal load ROM from the file 2. Than, on incoming migration we rewrite ROM from the incoming RAM block. If sizes mismatch we fail, like this: Size mismatch: 0000:00:03.0/virtio-net-pci.rom: 0x40000 != 0x80000: Invalid argument This is not ideal when we migrate to updated distribution: we have to keep old ROM files in new distribution and be careful around romfile property to load correct ROM file. Which is loaded actually just to allocate the ROM with correct length. Note, that romsize property doesn't really help: if we try to specify it when default romfile is larger, it fails with something like: romfile "efi-virtio.rom" (160768 bytes) is too large for ROM size 65536 Let's just ignore ROM file when romsize is specified and we are in incoming migration state. In other words, we need only to preallocate ROM of specified size, local ROM file is unrelated. This way: If romsize was specified on source, we just use same commandline as on source, and migration will work independently of local ROM files on target. If romsize was not specified on source (and we have mismatching local ROM file on target host), we have to specify romsize on target to match source romsize. romfile parameter may be kept same as on source or may be dropped, the file is not loaded anyway. As a bonus we avoid extra reading from ROM file on target. Note: when we don't have romsize parameter on source command line and need it for target, it may be calculated as aligned up to power of two size of ROM file on source (if we know, which file is it) or, alternatively it may be retrieved from source QEMU by QMP qom-get command, like { "execute": "qom-get", "arguments": { "path": "/machine/peripheral/CARD_ID/virtio-net-pci.rom[0]", "property": "size" } } Note: we have extra initialization of size variable to zero in pci_add_option_rom to avoid false-positive "error: ‘size’ may be used uninitialized" Suggested-by: Michael S. Tsirkin Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: David Hildenbrand Reviewed-by: Juan Quintela Message-Id: <20230522201740.88960-2-vsementsov@yandex-team.ru> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/pci/pci.c | 79 +++++++++++++++++++++++++++++++++++------------------------- 1 file changed, 46 insertions(+), 33 deletions(-) diff --git a/hw/pci/pci.c b/hw/pci/pci.c index bf38905b7d..e2eb4c3b4a 100644 --- a/hw/pci/pci.c +++ b/hw/pci/pci.c @@ -36,6 +36,7 @@ #include "migration/vmstate.h" #include "net/net.h" #include "sysemu/numa.h" +#include "sysemu/runstate.h" #include "sysemu/sysemu.h" #include "hw/loader.h" #include "qemu/error-report.h" @@ -2308,12 +2309,18 @@ static void pci_patch_ids(PCIDevice *pdev, uint8_t *ptr, uint32_t size) static void pci_add_option_rom(PCIDevice *pdev, bool is_default_rom, Error **errp) { - int64_t size; + int64_t size = 0; g_autofree char *path = NULL; - void *ptr; char name[32]; const VMStateDescription *vmsd; + /* + * In case of incoming migration ROM will come with migration stream, no + * reason to load the file. Neither we want to fail if local ROM file + * mismatches with specified romsize. + */ + bool load_file = !runstate_check(RUN_STATE_INMIGRATE); + if (!pdev->romfile || !strlen(pdev->romfile)) { return; } @@ -2343,32 +2350,35 @@ static void pci_add_option_rom(PCIDevice *pdev, bool is_default_rom, return; } - path = qemu_find_file(QEMU_FILE_TYPE_BIOS, pdev->romfile); - if (path == NULL) { - path = g_strdup(pdev->romfile); - } + if (load_file || pdev->romsize == -1) { + path = qemu_find_file(QEMU_FILE_TYPE_BIOS, pdev->romfile); + if (path == NULL) { + path = g_strdup(pdev->romfile); + } - size = get_image_size(path); - if (size < 0) { - error_setg(errp, "failed to find romfile \"%s\"", pdev->romfile); - return; - } else if (size == 0) { - error_setg(errp, "romfile \"%s\" is empty", pdev->romfile); - return; - } else if (size > 2 * GiB) { - error_setg(errp, "romfile \"%s\" too large (size cannot exceed 2 GiB)", - pdev->romfile); - return; - } - if (pdev->romsize != -1) { - if (size > pdev->romsize) { - error_setg(errp, "romfile \"%s\" (%u bytes) " - "is too large for ROM size %u", - pdev->romfile, (uint32_t)size, pdev->romsize); + size = get_image_size(path); + if (size < 0) { + error_setg(errp, "failed to find romfile \"%s\"", pdev->romfile); + return; + } else if (size == 0) { + error_setg(errp, "romfile \"%s\" is empty", pdev->romfile); + return; + } else if (size > 2 * GiB) { + error_setg(errp, + "romfile \"%s\" too large (size cannot exceed 2 GiB)", + pdev->romfile); return; } - } else { - pdev->romsize = pow2ceil(size); + if (pdev->romsize != -1) { + if (size > pdev->romsize) { + error_setg(errp, "romfile \"%s\" (%u bytes) " + "is too large for ROM size %u", + pdev->romfile, (uint32_t)size, pdev->romsize); + return; + } + } else { + pdev->romsize = pow2ceil(size); + } } vmsd = qdev_get_vmsd(DEVICE(pdev)); @@ -2379,15 +2389,18 @@ static void pci_add_option_rom(PCIDevice *pdev, bool is_default_rom, memory_region_init_rom(&pdev->rom, OBJECT(pdev), name, pdev->romsize, &error_fatal); - ptr = memory_region_get_ram_ptr(&pdev->rom); - if (load_image_size(path, ptr, size) < 0) { - error_setg(errp, "failed to load romfile \"%s\"", pdev->romfile); - return; - } + if (load_file) { + void *ptr = memory_region_get_ram_ptr(&pdev->rom); - if (is_default_rom) { - /* Only the default rom images will be patched (if needed). */ - pci_patch_ids(pdev, ptr, size); + if (load_image_size(path, ptr, size) < 0) { + error_setg(errp, "failed to load romfile \"%s\"", pdev->romfile); + return; + } + + if (is_default_rom) { + /* Only the default rom images will be patched (if needed). */ + pci_patch_ids(pdev, ptr, size); + } } pci_register_bar(pdev, PCI_ROM_SLOT, 0, &pdev->rom); -- 2.11.0