[PATCH 1/5] BIOS changes for irq0->inti2 override (v8)

[Beth Kon <eak@us.ibm.com>]

    bios: allow qemu to configure irq0->inti2 override

    Win2k8 expects the HPET interrupt on inti2, regardless of whether
    an override exists in the BIOS. And the HPET spec states that in legacy mode,
    timer interrupt is on inti2.

    The irq0->inti2 override will always be used unless the kernel cannot do irq
    routing (i.e., compatibility with old kernels). So if the kernel is capable,
    userspace sets up irq0->inti2 via the irq routing interface, and adds the
    irq0->inti2 override to the MADT interrupt source override table,
    and the mp table (for the no-acpi case).

    Signed-off-by: Beth Kon <eak@us.ibm.com>
    Signed-off-by: Avi Kivity <avi@redhat.com>

---
 kvm/bios/rombios32.c |   67 ++++++++++++++++++++++++++++++++++++++------------
 1 files changed, 51 insertions(+), 16 deletions(-)

diff --git a/kvm/bios/rombios32.c b/kvm/bios/rombios32.c
index 0369111..9e5370e 100755
--- a/kvm/bios/rombios32.c
+++ b/kvm/bios/rombios32.c
@@ -446,6 +446,9 @@ uint32_t cpuid_features;
 uint32_t cpuid_ext_features;
 unsigned long ram_size;
 uint64_t ram_end;
+#ifdef BX_QEMU
+uint8_t irq0_override;
+#endif
 #ifdef BX_USE_EBDA_TABLES
 unsigned long ebda_cur_addr;
 #endif
@@ -487,6 +490,7 @@ void wrmsr_smp(uint32_t index, uint64_t val)
 #define QEMU_CFG_ARCH_LOCAL     0x8000
 #define QEMU_CFG_ACPI_TABLES  (QEMU_CFG_ARCH_LOCAL + 0)
 #define QEMU_CFG_SMBIOS_ENTRIES  (QEMU_CFG_ARCH_LOCAL + 1)
+#define QEMU_CFG_IRQ0_OVERRIDE   (QEMU_CFG_ARCH_LOCAL + 2)
 
 int qemu_cfg_port;
 
@@ -555,6 +559,17 @@ uint64_t qemu_cfg_get64 (void)
 }
 #endif
 
+#ifdef BX_QEMU
+void irq0_override_probe(void)
+{
+    if(qemu_cfg_port) {
+        qemu_cfg_select(QEMU_CFG_IRQ0_OVERRIDE);
+        qemu_cfg_read(&irq0_override, 1);
+        return;
+    }
+}
+#endif
+
 void cpu_probe(void)
 {
     uint32_t eax, ebx, ecx, edx;
@@ -1153,7 +1168,14 @@ static void mptable_init(void)
     putstr(&q, "0.1         "); /* vendor id */
     putle32(&q, 0); /* OEM table ptr */
     putle16(&q, 0); /* OEM table size */
+#ifdef BX_QEMU
+    if (irq0_override)
+        putle16(&q, MAX_CPUS + 17); /* entry count */
+    else
+        putle16(&q, MAX_CPUS + 18); /* entry count */
+#else
     putle16(&q, MAX_CPUS + 18); /* entry count */
+#endif
     putle32(&q, 0xfee00000); /* local APIC addr */
     putle16(&q, 0); /* ext table length */
     putb(&q, 0); /* ext table checksum */
@@ -1197,6 +1219,13 @@ static void mptable_init(void)
 
     /* irqs */
     for(i = 0; i < 16; i++) {
+#ifdef BX_QEMU
+        /* One entry per ioapic interrupt destination. Destination 2 is covered
+         * by irq0->inti2 override (i == 0). Source IRQ 2 is unused
+         */
+        if (irq0_override && i == 2)
+            continue;
+#endif
         putb(&q, 3); /* entry type = I/O interrupt */
         putb(&q, 0); /* interrupt type = vectored interrupt */
         putb(&q, 0); /* flags: po=0, el=0 */
@@ -1204,7 +1233,12 @@ static void mptable_init(void)
         putb(&q, 0); /* source bus ID = ISA */
         putb(&q, i); /* source bus IRQ */
         putb(&q, ioapic_id); /* dest I/O APIC ID */
-        putb(&q, i); /* dest I/O APIC interrupt in */
+#ifdef BX_QEMU
+        if (irq0_override && i == 0)
+            putb(&q, 2); /* dest I/O APIC interrupt in */
+        else
+#endif
+            putb(&q, i); /* dest I/O APIC interrupt in */
     }
     /* patch length */
     len = q - mp_config_table;
@@ -1768,23 +1802,21 @@ void acpi_bios_init(void)
         io_apic->io_apic_id = smp_cpus;
         io_apic->address = cpu_to_le32(0xfec00000);
         io_apic->interrupt = cpu_to_le32(0);
-#ifdef BX_QEMU
-#ifdef HPET_WORKS_IN_KVM
         io_apic++;
-
-        int_override = (void *)io_apic;
-        int_override->type = APIC_XRUPT_OVERRIDE;
-        int_override->length = sizeof(*int_override);
-        int_override->bus = cpu_to_le32(0);
-        int_override->source = cpu_to_le32(0);
-        int_override->gsi = cpu_to_le32(2);
-        int_override->flags = cpu_to_le32(0);
-#endif
+        int_override = (struct madt_int_override*)(io_apic);
+#ifdef BX_QEMU
+        if (irq0_override) {
+            memset(int_override, 0, sizeof(*int_override));
+            int_override->type = APIC_XRUPT_OVERRIDE;
+            int_override->length = sizeof(*int_override);
+            int_override->source = 0;
+            int_override->gsi = 2;
+            int_override->flags = 0; /* conforms to bus specifications */
+            int_override++;
+        }
 #endif
-
-        int_override = (struct madt_int_override*)(io_apic + 1);
-        for ( i = 0; i < 16; i++ ) {
-            if ( PCI_ISA_IRQ_MASK & (1U << i) ) {
+        for (i = 0; i < 16; i++) {
+            if (PCI_ISA_IRQ_MASK & (1U << i)) {
                 memset(int_override, 0, sizeof(*int_override));
                 int_override->type   = APIC_XRUPT_OVERRIDE;
                 int_override->length = sizeof(*int_override);
@@ -2708,6 +2740,9 @@ void rombios32_init(uint32_t *s3_resume_vector, uint8_t *shutdown_flag)
 
     if (bios_table_cur_addr != 0) {
 
+#ifdef BX_QEMU
+        irq0_override_probe();
+#endif
         mptable_init();
 
         smbios_init();