KVM: VMX: Don't unblock vCPU w/ Posted IRQ if IRQs are disabled in guest

KVM: VMX: Don't unblock vCPU w/ Posted IRQ if IRQs are disabled in guest

BugLink: https://bugs.launchpad.net/bugs/1964361
[ Upstream commit 1831fa44df743a7cdffdf1c12c799bf6f3c12b8c ]

Don't configure the wakeup handler when a vCPU is blocking with IRQs
disabled, in which case any IRQ, posted or otherwise, should not be
recognized and thus should not wake the vCPU.

Fixes: bf9f6ac8d749 ("KVM: Update Posted-Interrupts Descriptor when vCPU is blocked")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211009021236.4122790-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>