Hi!

Recently, I encountered a seabios hanging problem. When I try to inject an MSI-X interrupt along with SMI in qemu like below:

*************** patch below*********************

diff --git a/target-i386/kvm.c b/target-i386/kvm.c- a/target-i386/kvm.c

--- a/target-i386/kvm.c

+++ b/target-i386/kvm.c

@@ -104,6 +104,7 @@ static uint32_t num_architectural_pmu_counters;

static int has_xsave;

static int has_xcrs;

static int has_pit_state2;

+static int msi_count;

static bool has_msr_mcg_ext_ctl;

@@ -2870,12 +2871, 26 @@ void kvm_arch_pre_run(CPUState *cpu, struct kvm_run *run)

DPRINTF("inject SMI\n");

+ MSIMessage msg = {.address = 0x0, .data = 0x4062};

+ if (msi_count == 1) {

+ ret = kvm_irqchip_send_msi(kvm_state, msg);

+ if (ret <0) {

+ QEMU_LOG(LOG_ALERT, "MSI lost %s\n", strerror(-ret));

+ }

+ msi_count++;

ret = kvm_vcpu_ioctl(cpu, KVM_SMI);

if (ret < 0)

**************patch above*************************

Then, when the vm will hang when booting.

There will be only one line in the vnc displayer:

"Guest has not initialized the display(yet)"

I went through the codes(kvm qemu seabios), and I found the check_irqs function in seabios will allow interrupt for a while.

When the interrupt triggered, the vcpu will lookup the seabios IDT table and jump to the interrupt handler.

However, in ivt_init(void), the entries from 0x60 to 0x66 will be cleared, which is configured by the patch below.

https://github.com/coreboot/seabios/commit/b164d2c1b8ff2dd764dcf064e2624dd4aa78c112

So the vcpu will jump to an undefined entry instead of the default entry.

=========================================================================

I removed the patch, and the bug seems to disappear. I wonder if this is an approprite solution.

=========================================================================

There is an another strange thing:

I opened kvm trace, and it showed like below:

************************

kvm_inj_exception: #UD(0x0)

kvm_entry: vcpu0

kvm_run: vcpu 0 to guest mode

kvm_run: vcpu 0 out guest mode

kvm_exit: reason EXCEPTION_NMI rip 0x3 info 0 80000306

kvm_emulate_insn: 0:3:f0 53 (real)