On Mon, Nov 09, 2015 at 08:32:53AM -0500, Kevin O'Connor wrote:
On Fri, Nov 06, 2015 at 09:12:34AM +0000, Xulei (Stone) wrote:
On Wed, Nov 04, 2015 at 08:48:20AM +0800, Gonglei wrote: I'm surprised you would see the above on a recent qemu/kvm though - as on a newer KVM I think the second reset would have to happen after HaveAttemptedReboot is set and prior to the memcpy in qemu_prep_reset() completing. Can you verify your KVM version?
I've tested on KVM-3.6 and KVM-4.1.3. On both of these versions, i can see this problem. I do like this: put a HA and a watchdog mechanism in a VM. Deliberately, let this VM lose heartbeat and don't feed dog. Then, after 2 minutes, a self-defined timeout, HA mechnism will issue a internal reboot command to the VM and watchdog mechanism will issue a "virsh reset" from the host. Then, aforementioned problem will occurs in high probability.
Ah, okay. I'm not sure what the best solution to this problem is.
After thinking about this further, I think we can move the HaveAttemptedReboot assignment after the memcpy. Does the SeaBIOS patch below fix things for you?
-Kevin
commit d0e9e2cca9fa6dacd2ad07081ef09c59be1ae945 Author: Kevin O'Connor kevin@koconnor.net Date: Mon Nov 9 15:00:19 2015 -0500
resume: Don't set HaveAttemptedReboot until after internal bios memcpy
Move the check for soft reboot loops from resume.c to shadow.c and only set the HaveAttemptedReboot flag after restoring the BIOS image. This prevents a hang if an external reboot request occurs during the BIOS memcpy.
Signed-off-by: Kevin O'Connor kevin@koconnor.net
diff --git a/src/fw/shadow.c b/src/fw/shadow.c index ee87d36..f2d0d65 100644 --- a/src/fw/shadow.c +++ b/src/fw/shadow.c @@ -156,6 +156,8 @@ make_bios_readonly(void) make_bios_readonly_intel(ShadowBDF, Q35_HOST_BRIDGE_PAM0); }
+u8 HaveAttemptedReboot VARLOW; + void qemu_prep_reset(void) { @@ -163,7 +165,13 @@ qemu_prep_reset(void) return; // QEMU doesn't map 0xc0000-0xfffff back to the original rom on a // reset, so do that manually before invoking a hard reset. + if (HaveAttemptedReboot) { + // Hard reboot has failed - try to shutdown machine. + dprintf(1, "Unable to hard-reboot machine - attempting shutdown.\n"); + apm_shutdown(); + } make_bios_writable(); memcpy(VSYMBOL(code32flat_start), VSYMBOL(code32flat_start) + BIOS_SRC_OFFSET , SYMBOL(code32flat_end) - SYMBOL(code32flat_start)); + HaveAttemptedReboot = 1; } diff --git a/src/resume.c b/src/resume.c index a5465d8..afeadcf 100644 --- a/src/resume.c +++ b/src/resume.c @@ -114,19 +114,10 @@ s3_resume(void) farcall16big(&br); }
-u8 HaveAttemptedReboot VARLOW; - // Attempt to invoke a hard-reboot. static void tryReboot(void) { - if (HaveAttemptedReboot) { - // Hard reboot has failed - try to shutdown machine. - dprintf(1, "Unable to hard-reboot machine - attempting shutdown.\n"); - apm_shutdown(); - } - HaveAttemptedReboot = 1; - dprintf(1, "Attempting a hard reboot\n");
// Setup for reset on qemu.