[RFC][PATCH 2/2] Finish hpet implementation for KVM

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

- add hpet to BIOS
- add disable/enable of kernel pit when hpet enters/leaves legacy mode

Signed-off-by: Beth Kon <eak@us.ibm.com>
diff --git a/bios/acpi-dsdt.dsl b/bios/acpi-dsdt.dsl
index d67616d..9981a1f 100755
--- a/bios/acpi-dsdt.dsl
+++ b/bios/acpi-dsdt.dsl
@@ -233,6 +233,24 @@ DefinitionBlock (
                     ,, , AddressRangeMemory, TypeStatic)
             })
         }
+        Device(HPET) {
+            Name(_HID,  EISAID("PNP0103"))
+            Name(_UID, 0)
+            Method (_STA, 0, NotSerialized) {
+                    Return(0x0F)
+            }
+            Name(_CRS, ResourceTemplate() {
+                DWordMemory(
+                    ResourceConsumer, PosDecode, MinFixed, MaxFixed,
+                    NonCacheable, ReadWrite,
+                    0x00000000,
+                    0xFED00000,
+                    0xFED003FF,
+                    0x00000000,
+                    0x00000400 /* 1K memory: FED00000 - FED003FF */
+                )
+            })
+        }
     }
 
     Scope(\_SB.PCI0) {
diff --git a/bios/rombios32.c b/bios/rombios32.c
index 84f15fb..17c3704 100755
--- a/bios/rombios32.c
+++ b/bios/rombios32.c
@@ -1272,7 +1272,7 @@ struct rsdp_descriptor         /* Root System Descriptor Pointer */
 struct rsdt_descriptor_rev1
 {
 	ACPI_TABLE_HEADER_DEF                           /* ACPI common table header */
-	uint32_t                             table_offset_entry [2]; /* Array of pointers to other */
+	uint32_t                             table_offset_entry [3]; /* Array of pointers to other */
 			 /* ACPI tables */
 } __attribute__((__packed__));
 
@@ -1412,6 +1412,31 @@ struct madt_processor_apic
 #endif
 } __attribute__((__packed__));
 
+/*
+ *  * ACPI 2.0 Generic Address Space definition.
+ *   */
+struct acpi_20_generic_address {
+    uint8_t  address_space_id;
+    uint8_t  register_bit_width;
+    uint8_t  register_bit_offset;
+    uint8_t  reserved;
+    uint64_t address;
+} __attribute__((__packed__));
+
+/*
+ *  * HPET Description Table
+ *   */
+struct acpi_20_hpet {
+    ACPI_TABLE_HEADER_DEF                           /* ACPI common table header */
+    uint32_t           timer_block_id;
+    struct acpi_20_generic_address addr;
+    uint8_t            hpet_number;
+    uint16_t           min_tick;
+    uint8_t            page_protect;
+} __attribute__((__packed__));
+
+#define ACPI_HPET_ADDRESS 0xFED00000UL
+
 struct madt_io_apic
 {
 	APIC_HEADER_DEF
@@ -1484,6 +1509,8 @@ void acpi_bios_init(void)
     struct facs_descriptor_rev1 *facs;
     struct multiple_apic_table *madt;
     uint8_t *dsdt;
+    struct acpi_20_hpet *hpet;
+    uint32_t hpet_addr;
     uint32_t base_addr, rsdt_addr, fadt_addr, addr, facs_addr, dsdt_addr;
     uint32_t acpi_tables_size, madt_addr, madt_size;
     int i;
@@ -1531,6 +1558,11 @@ void acpi_bios_init(void)
         madt_size += sizeof(struct madt_intsrcovr);
     addr += madt_size;
 
+    addr = (addr + 7) & ~7;
+    hpet_addr = addr;
+    hpet = (void *)(addr);
+    addr += sizeof(*hpet);
+
     acpi_tables_size = addr - base_addr;
 
     BX_INFO("ACPI tables: RSDP addr=0x%08lx ACPI DATA addr=0x%08lx size=0x%x\n",
@@ -1552,6 +1584,7 @@ void acpi_bios_init(void)
     memset(rsdt, 0, sizeof(*rsdt));
     rsdt->table_offset_entry[0] = cpu_to_le32(fadt_addr);
     rsdt->table_offset_entry[1] = cpu_to_le32(madt_addr);
+    rsdt->table_offset_entry[2] = cpu_to_le32(hpet_addr);
     acpi_build_table_header((struct acpi_table_header *)rsdt,
                             "RSDT", sizeof(*rsdt), 1);
 
@@ -1641,6 +1674,15 @@ void acpi_bios_init(void)
         }
         acpi_build_table_header((struct acpi_table_header *)madt,
                                 "APIC", madt_size, 1);
+        /* HPET */
+        memset(hpet, 0, sizeof(*hpet));
+        /* Note timer_block_id value must be kept in sync with value advertised by
+         * emulated hpet
+         */
+        hpet->timer_block_id = cpu_to_le32(0x8086a201);
+        hpet->addr.address = cpu_to_le32(ACPI_HPET_ADDRESS);
+        acpi_build_table_header((struct  acpi_table_header *)hpet,
+                                 "HPET", sizeof(*hpet), 1);
     }
 }
 
diff --git a/qemu/hw/hpet.c b/qemu/hw/hpet.c
index 7df2d05..80b2edd 100644
--- a/qemu/hw/hpet.c
+++ b/qemu/hw/hpet.c
@@ -30,8 +30,9 @@
 #include "console.h"
 #include "qemu-timer.h"
 #include "hpet_emul.h"
+#include "qemu-kvm.h"
 
-//#define HPET_DEBUG
+#define HPET_DEBUG
 #ifdef HPET_DEBUG
 #define dprintf printf
 #else
@@ -48,6 +49,43 @@ uint32_t hpet_in_legacy_mode(void)
         return 0;
 }
 
+static void hpet_kpit_enable(void)
+{
+    struct kvm_pit_state ps;
+    kvm_get_pit(kvm_context, &ps);
+    kvm_set_pit(kvm_context, &ps);
+}
+
+static void hpet_kpit_disable(void)
+{
+    struct kvm_pit_state ps;
+    kvm_get_pit(kvm_context, &ps);
+    ps.channels[0].mode = 0xff;
+    kvm_set_pit(kvm_context, &ps);
+}
+
+static void hpet_legacy_enable(void)
+{
+    if (qemu_kvm_pit_in_kernel()) {
+       hpet_kpit_disable();
+       dprintf("qemu: hpet disabled kernel pit\n");
+    } else {
+       hpet_pit_disable();
+       dprintf("qemu: hpet disabled userspace pit\n");
+    }
+}
+
+static void hpet_legacy_disable(void)
+{
+    if (qemu_kvm_pit_in_kernel()) {
+       hpet_kpit_enable();
+       dprintf("qemu: hpet enabled kernel pit\n");
+    } else {
+       hpet_pit_enable();
+       dprintf("qemu: hpet enabled userspace pit\n");
+    }
+}
+
 static uint32_t timer_int_route(struct HPETTimer *timer)
 {
     uint32_t route;
@@ -475,9 +513,9 @@ static void hpet_ram_writel(void *opaque, target_phys_addr_t addr,
                 }
                 /* i8254 and RTC are disabled when HPET is in legacy mode */
                 if (activating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
-                    hpet_pit_disable();
+                    hpet_legacy_enable();
                 } else if (deactivating_bit(old_val, new_val, HPET_CFG_LEGACY)) {
-                    hpet_pit_enable();
+                    hpet_legacy_disable();
                 }
                 break;
             case HPET_CFG + 4:
@@ -560,7 +598,7 @@ static void hpet_reset(void *opaque) {
          * hpet_reset is called due to system reset. At this point control must
          * be returned to pit until SW reenables hpet.
          */
-        hpet_pit_enable();
+        hpet_legacy_disable();
     count = 1;
 }
 
diff --git a/qemu/vl.c b/qemu/vl.c
index 21b3e51..c977deb 100644
--- a/qemu/vl.c
+++ b/qemu/vl.c
@@ -5877,6 +5877,12 @@ int main(int argc, char **argv, char **envp)
        kvm_init_ap();
         if (kvm_irqchip && !kvm_has_gsi_routing(kvm_context)) {
            irq0override = 0;
+
+           /* if kernel can't do irq routing, interrupt source
+            * override 0->2 can not be set up as required by hpet,
+            * so disable hpet.
+            */
+           no_hpet=1;
         }
     }