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Accepting request 986227 from home:lin_ma:branches:Virtualization

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Fix usb ehci boot failure (bsc#1192115)

OBS-URL: https://build.opensuse.org/request/show/986227
OBS-URL: https://build.opensuse.org/package/show/Virtualization/qemu?expand=0&rev=723
This commit is contained in:
Lin Ma 2022-07-01 12:45:39 +00:00 committed by Git OBS Bridge
parent c39ad145aa
commit 356a2ed499
3 changed files with 73 additions and 0 deletions
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64
hw-usb-hcd-ehci-fix-writeback-order.patch Normal file
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@ -0,0 +1,64 @@
From e4ad2b63e748643e12306d61aea7aaf5a41a0d3c Mon Sep 17 00:00:00 2001
From: Arnout Engelen <arnout@bzzt.net>
Date: Sun, 8 May 2022 17:32:22 +0200
Subject: [PATCH] hw/usb/hcd-ehci: fix writeback order
Git-commit: f471e8b060798f26a7fc339c6152f82f22a7b33d
References: bsc#1192115
The 'active' bit passes control over a qTD between the guest and the
controller: set to 1 by guest to enable execution by the controller,
and the controller sets it to '0' to hand back control to the guest.
ehci_state_writeback write two dwords to main memory using DMA:
the third dword of the qTD (containing dt, total bytes to transfer,
cpage, cerr and status) and the fourth dword of the qTD (containing
the offset).
This commit makes sure the fourth dword is written before the third,
avoiding a race condition where a new offset written into the qTD
by the guest after it observed the status going to go to '0' gets
overwritten by a 'late' DMA writeback of the previous offset.
This race condition could lead to 'cpage out of range (5)' errors,
and reproduced by:
./qemu-system-x86_64 -enable-kvm -bios $SEABIOS/bios.bin -m 4096 -device usb-ehci -blockdev driver=file,read-only=on,filename=/home/aengelen/Downloads/openSUSE-Tumbleweed-DVD-i586-Snapshot20220428-Media.iso,node-name=iso -device usb-storage,drive=iso,bootindex=0 -chardev pipe,id=shell,path=/tmp/pipe -device virtio-serial -device virtconsole,chardev=shell -device virtio-rng-pci -serial mon:stdio -nographic
(press a key, select 'Installation' (2), and accept the default
values. On my machine the 'cpage out of range' is reproduced while
loading the Linux Kernel about once per 7 attempts. With the fix in
this commit it no longer fails)
This problem was previously reported as a seabios problem in
https://mail.coreboot.org/hyperkitty/list/seabios@seabios.org/thread/OUTHT5ISSQJGXPNTUPY3O5E5EPZJCHM3/
and as a nixos CI build failure in
https://github.com/NixOS/nixpkgs/issues/170803
Signed-off-by: Arnout Engelen <arnout@bzzt.net>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
(cherry picked from commit f471e8b060798f26a7fc339c6152f82f22a7b33d)
Signed-off-by: Lin Ma <lma@suse.com>
---
hw/usb/hcd-ehci.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index 6caa7ac6c2..3464b2406e 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -2009,7 +2009,10 @@ static int ehci_state_writeback(EHCIQueue *q)
ehci_trace_qtd(q, NLPTR_GET(p->qtdaddr), (EHCIqtd *) &q->qh.next_qtd);
qtd = (uint32_t *) &q->qh.next_qtd;
addr = NLPTR_GET(p->qtdaddr);
- put_dwords(q->ehci, addr + 2 * sizeof(uint32_t), qtd + 2, 2);
+ /* First write back the offset */
+ put_dwords(q->ehci, addr + 3 * sizeof(uint32_t), qtd + 3, 1);
+ /* Then write back the token, clearing the 'active' bit */
+ put_dwords(q->ehci, addr + 2 * sizeof(uint32_t), qtd + 2, 1);
ehci_free_packet(p);
/*
--
2.34.1

7
qemu.changes
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@ -1,3 +1,10 @@
-------------------------------------------------------------------
Fri Jul 1 11:46:41 UTC 2022 - Lin Ma <lma@suse.com>
- Fix usb ehci boot failure (bsc#1192115)
* Patches added:
hw-usb-hcd-ehci-fix-writeback-order.patch
-------------------------------------------------------------------
Tue Jun 21 07:30:46 UTC 2022 - Dario Faggioli <dfaggioli@suse.com>

2
qemu.spec
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@ -250,6 +250,7 @@ Patch00106: python-aqmp-drop-_bind_hack.patch
Patch00107: block-qdict-Fix-Werror-maybe-uninitializ.patch
Patch00108: pci-fix-overflow-in-snprintf-string-form.patch
Patch00109: sphinx-change-default-language-to-en.patch
Patch00110: hw-usb-hcd-ehci-fix-writeback-order.patch
# Patches applied in roms/seabios/:
Patch01000: seabios-use-python2-explicitly-as-needed.patch
Patch01001: seabios-switch-to-python3-as-needed.patch
@ -1282,6 +1283,7 @@ This package records qemu testsuite results and represents successful testing.
%patch00107 -p1
%patch00108 -p1
%patch00109 -p1
%patch00110 -p1
%patch01000 -p1
%patch01001 -p1
%patch01002 -p1