Igor Druzhinin 239b50a863 OvmfPkg: End timer interrupt later to avoid stack overflow under load ... RestoreTPL called while at TPL_HIGH_LEVEL unconditionally enables interrupts even if called in interrupt handler. That opens a window while interrupt is not completely handled but another interrupt could be accepted. If a VM starts on a heavily loaded host hundreds of periodic timer interrupts might be queued while vCPU is descheduled (the behavior is typical for a Xen host). The next time vCPU is scheduled again all of them get delivered back to back causing OVMF to accept each one without finishing a previous one and cleaning up the stack. That quickly results in stack overflow and a triple fault. Fix it by postponing sending EOI until we finished processing the current tick giving interrupt handler opportunity to clean up the stack before accepting the next tick. Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> Message-Id: <1592275782-9369-1-git-send-email-igor.druzhinin@citrix.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2815 Acked-by: Laszlo Ersek <lersek@redhat.com> [lersek@redhat.com: add BZ ref; rewrap msg to silence PatchCheck.py]		2020-06-18 10:20:39 +00:00
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XenTimerDxe.c	OvmfPkg: End timer interrupt later to avoid stack overflow under load	2020-06-18 10:20:39 +00:00
XenTimerDxe.h	…
XenTimerDxe.inf	…