hvmloader: don't hard-code IO-APIC parameters

The IO-APIC address has variable bits determined by the PCI-to-ISA
bridge (albeit for now we refrain from actually evaluating them, as
there's still implicit rather than explicit agreement on the IO-APIC
base address between qemu and the hypervisor), and the IO-APIC version
should be read from the IO-APIC.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

tools/firmware/hvmloader/acpi/build.c

@@ -137,7 +137,7 @@ static struct acpi_20_madt *construct_madt(struct acpi_info *info)
     io_apic->type        = ACPI_IO_APIC;
     io_apic->length      = sizeof(*io_apic);
     io_apic->ioapic_id   = IOAPIC_ID;
-    io_apic->ioapic_addr = IOAPIC_BASE_ADDRESS;
+    io_apic->ioapic_addr = ioapic_base_address;
 
     lapic = (struct acpi_20_madt_lapic *)(io_apic + 1);
     info->nr_cpus = hvm_info->nr_vcpus;

tools/firmware/hvmloader/config.h

@@ -42,9 +42,10 @@ extern struct bios_config ovmf_config;
 #define PAGE_SHIFT 12
 #define PAGE_SIZE  (1ul << PAGE_SHIFT)
 
-#define IOAPIC_BASE_ADDRESS 0xfec00000
+extern uint32_t ioapic_base_address;
+extern uint8_t ioapic_version;
+
 #define IOAPIC_ID           0x01
-#define IOAPIC_VERSION      0x11
 
 #define LAPIC_BASE_ADDRESS  0xfee00000
 #define LAPIC_ID(vcpu_id)   ((vcpu_id) * 2)

tools/firmware/hvmloader/hvmloader.c

@@ -108,6 +108,9 @@ asm (
 
 unsigned long scratch_start = SCRATCH_PHYSICAL_ADDRESS;
 
+uint32_t ioapic_base_address = 0xfec00000;
+uint8_t ioapic_version;
+
 static void init_hypercalls(void)
 {
     uint32_t eax, ebx, ecx, edx;
@@ -185,6 +188,15 @@ static void init_vm86_tss(void)
 
 static void apic_setup(void)
 {
+    /*
+     * This would the The Right Thing To Do (tm), if only qemu negotiated
+     * with Xen where the IO-APIC actually sits (which is currently hard
+     * coded in Xen and can't be controlled externally). Uncomment this code
+     * once that changed.
+    ioapic_base_address |= (pci_readb(PCI_ISA_DEVFN, 0x80) & 0x3f) << 10;
+     */
+    ioapic_version = ioapic_read(0x01) & 0xff;
+
     /* Set the IOAPIC ID to the static value used in the MP/ACPI tables. */
     ioapic_write(0x00, IOAPIC_ID);
 

tools/firmware/hvmloader/mp_tables.c

@@ -227,9 +227,9 @@ static void fill_mp_ioapic_entry(struct mp_ioapic_entry *mpie)
 {
     mpie->type = ENTRY_TYPE_IOAPIC;
     mpie->ioapic_id = IOAPIC_ID;
-    mpie->ioapic_version = IOAPIC_VERSION;
+    mpie->ioapic_version = ioapic_version;
     mpie->ioapic_flags = 1; /* enabled */
-    mpie->ioapic_addr = IOAPIC_BASE_ADDRESS;
+    mpie->ioapic_addr = ioapic_base_address;
 }
 
 

tools/firmware/hvmloader/util.c

@@ -490,14 +490,14 @@ void *scratch_alloc(uint32_t size, uint32_t align)
 
 uint32_t ioapic_read(uint32_t reg)
 {
-    *(volatile uint32_t *)(IOAPIC_BASE_ADDRESS + 0x00) = reg;
-    return *(volatile uint32_t *)(IOAPIC_BASE_ADDRESS + 0x10);
+    *(volatile uint32_t *)(ioapic_base_address + 0x00) = reg;
+    return *(volatile uint32_t *)(ioapic_base_address + 0x10);
 }
 
 void ioapic_write(uint32_t reg, uint32_t val)
 {
-    *(volatile uint32_t *)(IOAPIC_BASE_ADDRESS + 0x00) = reg;
-    *(volatile uint32_t *)(IOAPIC_BASE_ADDRESS + 0x10) = val;
+    *(volatile uint32_t *)(ioapic_base_address + 0x00) = reg;
+    *(volatile uint32_t *)(ioapic_base_address + 0x10) = val;
 }
 
 uint32_t lapic_read(uint32_t reg)