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]
"OvmfPkg/8254TimerDxe" is replaced with a Xen-specific
EFI_TIMER_ARCH_PROTOCOL implementation. Also remove
8259InterruptControllerDxe as it is not used anymore.
This Timer uses the local APIC timer as time source as it can work on
both a Xen PVH guest and an HVM one.
Based on the "OvmfPkg/8254TimerDxe" implementation.
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1689
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20190813113119.14804-31-anthony.perard@citrix.com>
Igor Druzhinin
Anthony PERARD