summaryrefslogtreecommitdiffstats
path: root/arch/x86/lguest/boot.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/lguest/boot.c')
-rw-r--r--arch/x86/lguest/boot.c173
1 files changed, 153 insertions, 20 deletions
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index c1c1544b8485..ac4453d8520e 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -56,6 +56,9 @@
#include <linux/virtio_console.h>
#include <linux/pm.h>
#include <linux/export.h>
+#include <linux/pci.h>
+#include <linux/virtio_pci.h>
+#include <asm/acpi.h>
#include <asm/apic.h>
#include <asm/lguest.h>
#include <asm/paravirt.h>
@@ -71,6 +74,8 @@
#include <asm/stackprotector.h>
#include <asm/reboot.h> /* for struct machine_ops */
#include <asm/kvm_para.h>
+#include <asm/pci_x86.h>
+#include <asm/pci-direct.h>
/*G:010
* Welcome to the Guest!
@@ -831,6 +836,24 @@ static struct irq_chip lguest_irq_controller = {
.irq_unmask = enable_lguest_irq,
};
+static int lguest_enable_irq(struct pci_dev *dev)
+{
+ u8 line = 0;
+
+ /* We literally use the PCI interrupt line as the irq number. */
+ pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &line);
+ irq_set_chip_and_handler_name(line, &lguest_irq_controller,
+ handle_level_irq, "level");
+ dev->irq = line;
+ return 0;
+}
+
+/* We don't do hotplug PCI, so this shouldn't be called. */
+static void lguest_disable_irq(struct pci_dev *dev)
+{
+ WARN_ON(1);
+}
+
/*
* This sets up the Interrupt Descriptor Table (IDT) entry for each hardware
* interrupt (except 128, which is used for system calls), and then tells the
@@ -1181,25 +1204,136 @@ static __init char *lguest_memory_setup(void)
return "LGUEST";
}
+/* Offset within PCI config space of BAR access capability. */
+static int console_cfg_offset = 0;
+static int console_access_cap;
+
+/* Set up so that we access off in bar0 (on bus 0, device 1, function 0) */
+static void set_cfg_window(u32 cfg_offset, u32 off)
+{
+ write_pci_config_byte(0, 1, 0,
+ cfg_offset + offsetof(struct virtio_pci_cap, bar),
+ 0);
+ write_pci_config(0, 1, 0,
+ cfg_offset + offsetof(struct virtio_pci_cap, length),
+ 4);
+ write_pci_config(0, 1, 0,
+ cfg_offset + offsetof(struct virtio_pci_cap, offset),
+ off);
+}
+
+static void write_bar_via_cfg(u32 cfg_offset, u32 off, u32 val)
+{
+ /*
+ * We could set this up once, then leave it; nothing else in the *
+ * kernel should touch these registers. But if it went wrong, that
+ * would be a horrible bug to find.
+ */
+ set_cfg_window(cfg_offset, off);
+ write_pci_config(0, 1, 0,
+ cfg_offset + sizeof(struct virtio_pci_cap), val);
+}
+
+static void probe_pci_console(void)
+{
+ u8 cap, common_cap = 0, device_cap = 0;
+ /* Offset within BAR0 */
+ u32 device_offset;
+ u32 device_len;
+
+ /* Avoid recursive printk into here. */
+ console_cfg_offset = -1;
+
+ if (!early_pci_allowed()) {
+ printk(KERN_ERR "lguest: early PCI access not allowed!\n");
+ return;
+ }
+
+ /* We expect a console PCI device at BUS0, slot 1. */
+ if (read_pci_config(0, 1, 0, 0) != 0x10431AF4) {
+ printk(KERN_ERR "lguest: PCI device is %#x!\n",
+ read_pci_config(0, 1, 0, 0));
+ return;
+ }
+
+ /* Find the capabilities we need (must be in bar0) */
+ cap = read_pci_config_byte(0, 1, 0, PCI_CAPABILITY_LIST);
+ while (cap) {
+ u8 vndr = read_pci_config_byte(0, 1, 0, cap);
+ if (vndr == PCI_CAP_ID_VNDR) {
+ u8 type, bar;
+ u32 offset, length;
+
+ type = read_pci_config_byte(0, 1, 0,
+ cap + offsetof(struct virtio_pci_cap, cfg_type));
+ bar = read_pci_config_byte(0, 1, 0,
+ cap + offsetof(struct virtio_pci_cap, bar));
+ offset = read_pci_config(0, 1, 0,
+ cap + offsetof(struct virtio_pci_cap, offset));
+ length = read_pci_config(0, 1, 0,
+ cap + offsetof(struct virtio_pci_cap, length));
+
+ switch (type) {
+ case VIRTIO_PCI_CAP_DEVICE_CFG:
+ if (bar == 0) {
+ device_cap = cap;
+ device_offset = offset;
+ device_len = length;
+ }
+ break;
+ case VIRTIO_PCI_CAP_PCI_CFG:
+ console_access_cap = cap;
+ break;
+ }
+ }
+ cap = read_pci_config_byte(0, 1, 0, cap + PCI_CAP_LIST_NEXT);
+ }
+ if (!device_cap || !console_access_cap) {
+ printk(KERN_ERR "lguest: No caps (%u/%u/%u) in console!\n",
+ common_cap, device_cap, console_access_cap);
+ return;
+ }
+
+ /*
+ * Note that we can't check features, until we've set the DRIVER
+ * status bit. We don't want to do that until we have a real driver,
+ * so we just check that the device-specific config has room for
+ * emerg_wr. If it doesn't support VIRTIO_CONSOLE_F_EMERG_WRITE
+ * it should ignore the access.
+ */
+ if (device_len < (offsetof(struct virtio_console_config, emerg_wr)
+ + sizeof(u32))) {
+ printk(KERN_ERR "lguest: console missing emerg_wr field\n");
+ return;
+ }
+
+ console_cfg_offset = device_offset;
+ printk(KERN_INFO "lguest: Console via virtio-pci emerg_wr\n");
+}
+
/*
* We will eventually use the virtio console device to produce console output,
- * but before that is set up we use LHCALL_NOTIFY on normal memory to produce
- * console output.
+ * but before that is set up we use the virtio PCI console's backdoor mmio
+ * access and the "emergency" write facility (which is legal even before the
+ * device is configured).
*/
static __init int early_put_chars(u32 vtermno, const char *buf, int count)
{
- char scratch[17];
- unsigned int len = count;
+ /* If we couldn't find PCI console, forget it. */
+ if (console_cfg_offset < 0)
+ return count;
- /* We use a nul-terminated string, so we make a copy. Icky, huh? */
- if (len > sizeof(scratch) - 1)
- len = sizeof(scratch) - 1;
- scratch[len] = '\0';
- memcpy(scratch, buf, len);
- hcall(LHCALL_NOTIFY, __pa(scratch), 0, 0, 0);
+ if (unlikely(!console_cfg_offset)) {
+ probe_pci_console();
+ if (console_cfg_offset < 0)
+ return count;
+ }
- /* This routine returns the number of bytes actually written. */
- return len;
+ write_bar_via_cfg(console_access_cap,
+ console_cfg_offset
+ + offsetof(struct virtio_console_config, emerg_wr),
+ buf[0]);
+ return 1;
}
/*
@@ -1400,14 +1534,6 @@ __init void lguest_init(void)
atomic_notifier_chain_register(&panic_notifier_list, &paniced);
/*
- * The IDE code spends about 3 seconds probing for disks: if we reserve
- * all the I/O ports up front it can't get them and so doesn't probe.
- * Other device drivers are similar (but less severe). This cuts the
- * kernel boot time on my machine from 4.1 seconds to 0.45 seconds.
- */
- paravirt_disable_iospace();
-
- /*
* This is messy CPU setup stuff which the native boot code does before
* start_kernel, so we have to do, too:
*/
@@ -1436,6 +1562,13 @@ __init void lguest_init(void)
/* Register our very early console. */
virtio_cons_early_init(early_put_chars);
+ /* Don't let ACPI try to control our PCI interrupts. */
+ disable_acpi();
+
+ /* We control them ourselves, by overriding these two hooks. */
+ pcibios_enable_irq = lguest_enable_irq;
+ pcibios_disable_irq = lguest_disable_irq;
+
/*
* Last of all, we set the power management poweroff hook to point to
* the Guest routine to power off, and the reboot hook to our restart