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[Xen-changelog] [qemu-xen-4.2-testing] qemu-stubdom: prevent useless medium change

Date: Tue, 11 Dec 2012 16:11:11 +0000

Delivery-date: Tue, 11 Dec 2012 16:11:23 +0000

List-id: "Change log for Mercurial $receive only$" <xen-changelog.lists.xen.org>

commit 6f5e128677e2d5795cf1ade4080fb69d5e442887 Author: Roger Pau Monne <roger.pau@xxxxxxxxxx> Date: Thu Dec 6 12:35:58 2012 +0000 qemu-stubdom: prevent useless medium change qemu-stubdom was stripping the prefix from the "params" xenstore key in xenstore_parse_domain_config, which was then saved stripped in a variable. In xenstore_process_event we compare the "param" from xenstore (not stripped) with the stripped "param" saved in the variable, which leads to a medium change (even if there isn't any), since we are comparing something like aio:/path/to/file with /path/to/file. This only happens one time, since xenstore_parse_domain_config is the only place where we strip the prefix. The result of this bug is the following: xs_read_watch() -> /local/domain/0/backend/qdisk/19/5632/params hdc close(7) close blk: backend=/local/domain/0/backend/qdisk/19/5632 node=/local/domain/19/device/vbd/5632 (XEN) HVM18: HVM Loader (XEN) HVM18: Detected Xen v4.3-unstable (XEN) HVM18: Xenbus rings @0xfeffc000, event channel 4 (XEN) HVM18: System requested ROMBIOS (XEN) HVM18: CPU speed is 2400 MHz (XEN) irq.c:270: Dom18 PCI link 0 changed 0 -> 5 (XEN) HVM18: PCI-ISA link 0 routed to IRQ5 (XEN) irq.c:270: Dom18 PCI link 1 changed 0 -> 10 (XEN) HVM18: PCI-ISA link 1 routed to IRQ10 (XEN) irq.c:270: Dom18 PCI link 2 changed 0 -> 11 (XEN) HVM18: PCI-ISA link 2 routed to IRQ11 (XEN) irq.c:270: Dom18 PCI link 3 changed 0 -> 5 (XEN) HVM18: PCI-ISA link 3 routed to IRQ5 (XEN) HVM18: pci dev 01:3 INTA->IRQ10 (XEN) HVM18: pci dev 03:0 INTA->IRQ5 (XEN) HVM18: pci dev 04:0 INTA->IRQ5 (XEN) HVM18: pci dev 02:0 bar 10 size lx: 02000000 (XEN) HVM18: pci dev 03:0 bar 14 size lx: 01000000 (XEN) HVM18: pci dev 02:0 bar 14 size lx: 00001000 (XEN) HVM18: pci dev 03:0 bar 10 size lx: 00000100 (XEN) HVM18: pci dev 04:0 bar 10 size lx: 00000100 (XEN) HVM18: pci dev 04:0 bar 14 size lx: 00000100 (XEN) HVM18: pci dev 01:1 bar 20 size lx: 00000010 (XEN) HVM18: Multiprocessor initialisation: (XEN) HVM18: - CPU0 ... 36-bit phys ... fixed MTRRs ... var MTRRs [2/8] ... done. (XEN) HVM18: - CPU1 ... 36-bit phys ... fixed MTRRs ... var MTRRs [2/8] ... done. (XEN) HVM18: Testing HVM environment: (XEN) HVM18: - REP INSB across page boundaries ... passed (XEN) HVM18: - GS base MSRs and SWAPGS ... passed (XEN) HVM18: Passed 2 of 2 tests (XEN) HVM18: Writing SMBIOS tables ... (XEN) HVM18: Loading ROMBIOS ... (XEN) HVM18: 9660 bytes of ROMBIOS high-memory extensions: (XEN) HVM18: Relocating to 0xfc001000-0xfc0035bc ... done (XEN) HVM18: Creating MP tables ... (XEN) HVM18: Loading Cirrus VGABIOS ... (XEN) HVM18: Loading PCI Option ROM ... (XEN) HVM18: - Manufacturer: http://ipxe.org (XEN) HVM18: - Product name: iPXE (XEN) HVM18: Option ROMs: (XEN) HVM18: c0000-c8fff: VGA BIOS (XEN) HVM18: c9000-d8fff: Etherboot ROM (XEN) HVM18: Loading ACPI ... (XEN) HVM18: vm86 TSS at fc00f680 (XEN) HVM18: BIOS map: (XEN) HVM18: f0000-fffff: Main BIOS (XEN) HVM18: E820 table: (XEN) HVM18: [00]: 00000000:00000000 - 00000000:0009e000: RAM (XEN) HVM18: [01]: 00000000:0009e000 - 00000000:000a0000: RESERVED (XEN) HVM18: HOLE: 00000000:000a0000 - 00000000:000e0000 (XEN) HVM18: [02]: 00000000:000e0000 - 00000000:00100000: RESERVED (XEN) HVM18: [03]: 00000000:00100000 - 00000000:3f800000: RAM (XEN) HVM18: HOLE: 00000000:3f800000 - 00000000:fc000000 (XEN) HVM18: [04]: 00000000:fc000000 - 00000001:00000000: RESERVED (XEN) HVM18: Invoking ROMBIOS ... (XEN) HVM18: $Revision: 1.221 $ $Date: 2008/12/07 17:32:29 $ (XEN) stdvga.c:147:d18 entering stdvga and caching modes (XEN) HVM18: VGABios $Id: vgabios.c,v 1.67 2008/01/27 09:44:12 vruppert Exp $ (XEN) HVM18: Bochs BIOS - build: 06/23/99 (XEN) HVM18: $Revision: 1.221 $ $Date: 2008/12/07 17:32:29 $ (XEN) HVM18: Options: apmbios pcibios eltorito PMM (XEN) HVM18: (XEN) HVM18: ata0-0: PCHS=16383/16/63 translation=lba LCHS=1024/255/63 (XEN) HVM18: ata0 master: QEMU HARDDISK ATA-7 Hard-Disk (10240 MBytes) (XEN) HVM18: IDE time out (XEN) HVM18: ata1 master: QEMU DVD-ROM ATAPI-4 CD-Rom/DVD-Rom (XEN) HVM18: IDE time out (XEN) HVM18: (XEN) HVM18: (XEN) HVM18: (XEN) HVM18: Press F12 for boot menu. (XEN) HVM18: (XEN) HVM18: Booting from CD-Rom... (XEN) HVM18: ata_is_ready returned 1 (XEN) HVM18: CDROM boot failure code : 0003 (XEN) HVM18: Boot from CD-Rom failed: could not read the boot disk (XEN) HVM18: (XEN) HVM18: (XEN) HVM18: No bootable device. (XEN) HVM18: Powering off in 30 seconds. ******************* BLKFRONT for /local/domain/19/device/vbd/5632 ********** backend at /local/domain/0/backend/qdisk/19/5632 Failed to read /local/domain/0/backend/qdisk/19/5632/feature-flush-cache. 284420 sectors of 512 bytes ************************** blk_open(/local/domain/19/device/vbd/5632) -> 7 As seen in this trace, the medium change happens just when the guest is booting, which leads to the guest not being able to boot because the BIOS is not able to access the device. This is a regression from Xen 4.1, which is able to boot from "file:/" based backends when using stubdomains. [ By inspection, this patch does not change the flow for the non-stubdom case. -iwj] Signed-off-by: Roger Pau MonnÃ© <roger.pau@xxxxxxxxxx> Acked-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx> (cherry picked from commit 6a0cf3786f1964fdf5a17f88f26cb499f4e89c81) --- xenstore.c | 10 ++++++---- 1 files changed, 6 insertions(+), 4 deletions(-) diff --git a/xenstore.c b/xenstore.c index 1857160..d3a4588 100644 --- a/xenstore.c +++ b/xenstore.c @@ -614,6 +614,12 @@ void xenstore_parse_domain_config(int hvm_domid) if (pasprintf(&danger_buf, "%s/device/vbd/%s", danger_path, e_danger[i]) == -1) continue; if (bdrv_open2(bs, danger_buf, BDRV_O_CACHE_WB /* snapshot and write-back */, &bdrv_raw) == 0) { + if (pasprintf(&buf, "%s/params", bpath) == -1) + continue; + free(params); + params = xs_read(xsh, XBT_NULL, buf, &len); + if (params == NULL) + continue; pstrcpy(bs->filename, sizeof(bs->filename), params); } #else @@ -667,11 +673,7 @@ void xenstore_parse_domain_config(int hvm_domid) drives_table[nb_drives].bdrv = bs; drives_table[nb_drives].used = 1; -#ifdef CONFIG_STUBDOM - media_filename[nb_drives] = strdup(danger_buf); -#else media_filename[nb_drives] = strdup(bs->filename); -#endif nb_drives++; } -- generated by git-patchbot for /home/xen/git/qemu-xen-4.2-testing.git

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