Add support for use as Xen HVM BIOS.

SeaBIOS is called by Xen's hvmloader which does the basic platform
setup (PCI, APIC, etc) and provides the various BIOS tables. Therefore
avoid re-doing that setup and copy out the tables as necessary. A
simple data structure is defined to pass the addresses of these
tables.

This patch also establishes the basic infrastructure to make
hypercalls, although it currently only uses it to query the hypervisor
version.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>

1 files changed, 149 insertions, 0 deletions

diff --git a/src/xen.c b/src/xen.c
new file mode 100644
index 0000000..4072793
--- /dev/null
+++ b/src/xen.c
@@ -0,0 +1,149 @@
+// Xen HVM support
+//
+// Copyright (C) 2011 Citrix Systems.
+//
+// This file may be distributed under the terms of the GNU LGPLv3 license.
+
+#include "config.h"
+#include "xen.h"
+
+#include "memmap.h" // add_e820
+#include "types.h" // ASM32FLAT
+#include "util.h" // copy_acpi_rsdp
+
+#define INFO_PHYSICAL_ADDRESS 0x00001000
+
+u32 xen_cpuid_base = 0;
+
+struct xen_seabios_info {
+    char signature[14]; /* XenHVMSeaBIOS\0 */
+    u8 length;     /* Length of this struct */
+    u8 checksum;   /* Set such that the sum over bytes 0..length == 0 */
+    /*
+     * Physical address of an array of tables_nr elements.
+     *
+     * Each element is a 32 bit value contianing the physical address
+     * of a BIOS table.
+     */
+    u32 tables;
+    u32 tables_nr;
+    /*
+     * Physical address of the e820 table, contains e820_nr entries.
+     */
+    u32 e820;
+    u32 e820_nr;
+} PACKED;
+
+static void validate_info(struct xen_seabios_info *t)
+{
+    if ( memcmp(t->signature, "XenHVMSeaBIOS", 14) )
+        panic("Bad Xen info signature\n");
+
+    if ( t->length < sizeof(struct xen_seabios_info) )
+        panic("Bad Xen info length\n");
+
+    if (checksum(t, t->length) != 0)
+        panic("Bad Xen info checksum\n");
+}
+
+void xen_probe(void)
+{
+    u32 base, eax, ebx, ecx, edx;
+    char signature[13];
+
+    if (!CONFIG_XEN)
+        return;
+
+    for (base = 0x40000000; base < 0x40010000; base += 0x100) {
+        cpuid(base, &eax, &ebx, &ecx, &edx);
+        memcpy(signature + 0, &ebx, 4);
+        memcpy(signature + 4, &ecx, 4);
+        memcpy(signature + 8, &edx, 4);
+        signature[12] = 0;
+
+        dprintf(1, "Found hypervisor signature \"%s\" at %x\n",
+                signature, base);
+        if (strcmp(signature, "XenVMMXenVMM") == 0) {
+            if ((eax - base) < 2)
+                panic("Insufficient Xen cpuid leaves. eax=%x at base %x\n",
+                      eax, base);
+            xen_cpuid_base = base;
+            break;
+        }
+    }
+}
+
+static int hypercall_xen_version( int cmd, void *arg)
+{
+    return _hypercall2(int, xen_version, cmd, arg);
+}
+
+/* Fill in hypercall transfer pages. */
+void xen_init_hypercalls(void)
+{
+    u32 eax, ebx, ecx, edx;
+    xen_extraversion_t extraversion;
+    unsigned long i;
+
+    if (!usingXen())
+        return;
+
+    cpuid(xen_cpuid_base + 2, &eax, &ebx, &ecx, &edx);
+
+    xen_hypercall_page = (unsigned long)memalign_high(PAGE_SIZE, eax*PAGE_SIZE);
+    if (!xen_hypercall_page)
+        panic("unable to allocate Xen hypercall page\n");
+
+    dprintf(1, "Allocated Xen hypercall page at %lx\n", xen_hypercall_page);
+    for ( i = 0; i < eax; i++ )
+        wrmsr(ebx, xen_hypercall_page + (i << 12) + i);
+
+    /* Print version information. */
+    cpuid(xen_cpuid_base + 1, &eax, &ebx, &ecx, &edx);
+    hypercall_xen_version(XENVER_extraversion, extraversion);
+    dprintf(1, "Detected Xen v%u.%u%s\n", eax >> 16, eax & 0xffff, extraversion);
+}
+
+void xen_copy_biostables(void)
+{
+    struct xen_seabios_info *info = (void *)INFO_PHYSICAL_ADDRESS;
+    u32 *tables = (u32 *)info->tables;
+    int i;
+
+    dprintf(1, "xen: copy BIOS tables...\n");
+    for (i=0; i<info->tables_nr; i++) {
+        void *table = (void *)tables[i];
+        copy_acpi_rsdp(table);
+        copy_mptable(table);
+        copy_pir(table);
+        copy_smbios(table);
+    }
+}
+
+void xen_setup(void)
+{
+    u64 maxram = 0, maxram_over4G = 0;
+    int i;
+    struct xen_seabios_info *info = (void *)INFO_PHYSICAL_ADDRESS;
+    struct e820entry *e820 = (struct e820entry *)info->e820;
+    validate_info(info);
+
+    dprintf(1, "xen: copy e820...\n");
+
+    for (i = 0; i < info->e820_nr; i++) {
+        struct e820entry *e = &e820[i];
+        if (e->type == E820_ACPI || e->type == E820_RAM) {
+            u64 end = e->start + e->size;
+            if (end > 0x100000000ull) {
+                end -= 0x100000000ull;
+                if (end > maxram_over4G)
+                    maxram_over4G = end;
+            } else if (end > maxram)
+                maxram = end;
+        }
+        add_e820(e->start, e->size, e->type);
+    }
+
+    RamSize = maxram;
+    RamSizeOver4G = maxram_over4G;
+}