xen: add CPU microcode update driver

Xen does all the hard work for us, including choosing the right update
method for this cpu type and actually doing it for all cpus.  We just
need to supply it with the firmware blob.

Because Xen updates all CPUs (and the kernel's virtual cpu numbers have
no fixed relationship with the underlying physical cpus), we only bother
doing anything for cpu "0".

[ Impact: allow CPU microcode update in Xen dom0 ]
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index 24215072d0e1e5894d4643634bfe1ef9786eef55..22677d67dffbe0a5fe15f34e9807545a4edbe5cf 100644 (file)
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -61,4 +61,13 @@ static inline struct microcode_ops * __init init_amd_microcode(void)
 }
 #endif
 
+#ifdef CONFIG_MICROCODE_XEN
+extern struct microcode_ops * __init init_xen_microcode(void);
+#else
+static inline struct microcode_ops * __init init_xen_microcode(void)
+{
+       return NULL;
+}
+#endif
+
 #endif /* _ASM_X86_MICROCODE_H */

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 7338ef2218bc0687f6bfc392ecfeca8a48ca0b56..d34362a466a7843ca1e92683d1a6850710b6f4e3 100644 (file)
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -105,6 +105,7 @@ obj-$(CONFIG_PCSPKR_PLATFORM)       += pcspeaker.o
 microcode-y                            := microcode_core.o
 microcode-$(CONFIG_MICROCODE_INTEL)    += microcode_intel.o
 microcode-$(CONFIG_MICROCODE_AMD)      += microcode_amd.o
+microcode-$(CONFIG_MICROCODE_XEN)      += microcode_xen.o
 obj-$(CONFIG_MICROCODE)                        += microcode.o
 
 obj-$(CONFIG_X86_CHECK_BIOS_CORRUPTION) += check.o

diff --git a/arch/x86/kernel/microcode_core.c b/arch/x86/kernel/microcode_core.c
index f9242800bc84073cbb284fc3c6bb0fbe0c2e7f12..ecbcbc0369207809b6d34a88d3d6e7b65bc80c7a 100644 (file)
--- a/arch/x86/kernel/microcode_core.c
+++ b/arch/x86/kernel/microcode_core.c
@@ -84,6 +84,7 @@
 #include <linux/mm.h>
 #include <linux/syscore_ops.h>
 
+#include <xen/xen.h>
 #include <asm/microcode.h>
 #include <asm/processor.h>
 
@@ -501,7 +502,9 @@ static int __init microcode_init(void)
        struct cpuinfo_x86 *c = &cpu_data(0);
        int error;
 
-       if (c->x86_vendor == X86_VENDOR_INTEL)
+       if (xen_pv_domain())
+               microcode_ops = init_xen_microcode();
+       else if (c->x86_vendor == X86_VENDOR_INTEL)
                microcode_ops = init_intel_microcode();
        else if (c->x86_vendor == X86_VENDOR_AMD)
                microcode_ops = init_amd_microcode();

diff --git a/arch/x86/kernel/microcode_xen.c b/arch/x86/kernel/microcode_xen.c
new file mode 100644 (file)
index 0000000..9d2a06b
--- /dev/null
+++ b/arch/x86/kernel/microcode_xen.c
@@ -0,0 +1,198 @@
+/*
+ * Xen microcode update driver
+ *
+ * Xen does most of the work here.  We just pass the whole blob into
+ * Xen, and it will apply it to all CPUs as appropriate.  Xen will
+ * worry about how different CPU models are actually updated.
+ */
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/firmware.h>
+#include <linux/vmalloc.h>
+#include <linux/uaccess.h>
+
+#include <asm/microcode.h>
+
+#include <xen/xen.h>
+#include <xen/interface/platform.h>
+#include <xen/interface/xen.h>
+
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+
+MODULE_DESCRIPTION("Xen microcode update driver");
+MODULE_LICENSE("GPL");
+
+struct xen_microcode {
+       size_t len;
+       char data[0];
+};
+
+static int xen_microcode_update(int cpu)
+{
+       int err;
+       struct xen_platform_op op;
+       struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+       struct xen_microcode *uc = uci->mc;
+
+       if (uc == NULL || uc->len == 0) {
+               /*
+                * We do all cpus at once, so we don't need to do
+                * other cpus explicitly (besides, these vcpu numbers
+                * have no relationship to underlying physical cpus).
+                */
+               return 0;
+       }
+
+       op.cmd = XENPF_microcode_update;
+       set_xen_guest_handle(op.u.microcode.data, uc->data);
+       op.u.microcode.length = uc->len;
+
+       err = HYPERVISOR_dom0_op(&op);
+
+       if (err != 0)
+               printk(KERN_WARNING "microcode_xen: microcode update failed: %d\n", err);
+
+       return err;
+}
+
+static enum ucode_state xen_request_microcode_fw(int cpu, struct device *device)
+{
+       char name[30];
+       struct cpuinfo_x86 *c = &cpu_data(cpu);
+       const struct firmware *firmware;
+       struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+       enum ucode_state ret;
+       struct xen_microcode *uc;
+       size_t size;
+       int err;
+
+       switch (c->x86_vendor) {
+       case X86_VENDOR_INTEL:
+               snprintf(name, sizeof(name), "intel-ucode/%02x-%02x-%02x",
+                        c->x86, c->x86_model, c->x86_mask);
+               break;
+
+       case X86_VENDOR_AMD:
+               snprintf(name, sizeof(name), "amd-ucode/microcode_amd.bin");
+               break;
+
+       default:
+               return UCODE_NFOUND;
+       }
+
+       err = request_firmware(&firmware, name, device);
+       if (err) {
+               pr_debug("microcode: data file %s load failed\n", name);
+               return UCODE_NFOUND;
+       }
+
+       /*
+        * Only bother getting real firmware for cpu 0; the others get
+        * dummy placeholders.
+        */
+       if (cpu == 0)
+               size = firmware->size;
+       else
+               size = 0;
+
+       if (uci->mc != NULL) {
+               vfree(uci->mc);
+               uci->mc = NULL;
+       }
+
+       ret = UCODE_ERROR;
+       uc = vmalloc(sizeof(*uc) + size);
+       if (uc == NULL)
+               goto out;
+
+       ret = UCODE_OK;
+       uc->len = size;
+       memcpy(uc->data, firmware->data, uc->len);
+
+       uci->mc = uc;
+
+out:
+       release_firmware(firmware);
+
+       return ret;
+}
+
+static enum ucode_state xen_request_microcode_user(int cpu,
+                                                  const void __user *buf, size_t size)
+{
+       struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+       struct xen_microcode *uc;
+       enum ucode_state ret;
+       size_t unread;
+
+       if (cpu != 0) {
+               /* No real firmware for non-zero cpus; just store a
+                  placeholder */
+               size = 0;
+       }
+
+       if (uci->mc != NULL) {
+               vfree(uci->mc);
+               uci->mc = NULL;
+       }
+
+       ret = UCODE_ERROR;
+       uc = vmalloc(sizeof(*uc) + size);
+       if (uc == NULL)
+               goto out;
+
+       uc->len = size;
+
+       ret = UCODE_NFOUND;
+
+       unread = copy_from_user(uc->data, buf, size);
+
+       if (unread != 0) {
+               printk(KERN_WARNING "failed to read %zd of %zd bytes at %p -> %p\n",
+                      unread, size, buf, uc->data);
+               goto out;
+       }
+
+       ret = UCODE_OK;
+
+out:
+       if (ret == 0)
+               uci->mc = uc;
+       else
+               vfree(uc);
+
+       return ret;
+}
+
+static void xen_microcode_fini_cpu(int cpu)
+{
+       struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+
+       vfree(uci->mc);
+       uci->mc = NULL;
+}
+
+static int xen_collect_cpu_info(int cpu, struct cpu_signature *sig)
+{
+       sig->sig = 0;
+       sig->pf = 0;
+       sig->rev = 0;
+
+       return 0;
+}
+
+static struct microcode_ops microcode_xen_ops = {
+       .request_microcode_user           = xen_request_microcode_user,
+       .request_microcode_fw             = xen_request_microcode_fw,
+       .collect_cpu_info                 = xen_collect_cpu_info,
+       .apply_microcode                  = xen_microcode_update,
+       .microcode_fini_cpu               = xen_microcode_fini_cpu,
+};
+
+struct microcode_ops * __init init_xen_microcode(void)
+{
+       if (!xen_initial_domain())
+               return NULL;
+       return &microcode_xen_ops;
+}

diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 5cc821cb2e0968090501e8c6e5af36353d5e2f87..4d04d4f1acfbb96816761b1f698bd44df2eda2dd 100644 (file)
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -57,3 +57,7 @@ config XEN_DEBUG
        help
          Enable various WARN_ON checks in the Xen MMU code.
          Enabling this option WILL incur a significant performance overhead.
+
+config MICROCODE_XEN
+       def_bool y
+       depends on XEN_DOM0 && MICROCODE