[Qemu-devel] [PATCH 25/40] xenner: kernel: KVM PV code

[Alexander Graf <agraf@suse.de>]

Xenner uses KVM's PV functionality for timekeeping. If we don't find
KVM clocksource support, we try to emulate it as good as we can.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 pc-bios/xenner/xenner-pv.c |  186 ++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 186 insertions(+), 0 deletions(-)
 create mode 100644 pc-bios/xenner/xenner-pv.c

diff --git a/pc-bios/xenner/xenner-pv.c b/pc-bios/xenner/xenner-pv.c
new file mode 100644
index 0000000..98218a9
--- /dev/null
+++ b/pc-bios/xenner/xenner-pv.c
@@ -0,0 +1,186 @@
+/*
+ *  Copyright (C) Red Hat 2007
+ *  Copyright (C) Novell Inc. 2010
+ *
+ *  Author(s): Gerd Hoffmann <kraxel@redhat.com>
+ *             Alexander Graf <agraf@suse.de>
+ *
+ *  Xenner KVM PV integration
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; under version 2 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "xenner.h"
+
+/* --------------------------------------------------------------------- */
+
+const char *feature_bits[32] = {
+    [ KVM_FEATURE_CLOCKSOURCE  ] = "clocksource",
+    [ KVM_FEATURE_NOP_IO_DELAY ] = "nop-iodelay",
+    [ KVM_FEATURE_MMU_OP       ] = "mmu-op",
+};
+
+int pv_have_clock;
+
+/* --------------------------------------------------------------------- */
+
+void pv_clock_update(int wakeup)
+{
+    static int wakeups;
+    static int update;
+
+    if (wakeup) {
+        /* after halt() -- update clock unconditionally */
+        update = 1;
+        wakeups++;
+    } else {
+        /* timer irq -- update only if needed */
+        update = (0 == wakeups);
+        wakeups = 0;
+    }
+
+    /* vmexit to userspace so xenner has a chance to update systime */
+    if (update) {
+        if (pv_have_clock) {
+            emudev_cmd(EMUDEV_CMD_NOP, 0);
+        } else {
+            struct xen_cpu *cpu = get_cpu();
+
+            cpu->v.vcpu_info->time.tsc_timestamp = rdtsc();
+            cpu->v.vcpu_info->time.system_time =
+                cpu->v.vcpu_info->time.tsc_timestamp;
+
+            cpu->v.vcpu_info->time.version+=2;
+            cpu->v.vcpu_info->time.tsc_timestamp = rdtsc();
+            cpu->v.vcpu_info->time.system_time =
+                cpu->v.vcpu_info->time.tsc_timestamp;
+        }
+    }
+}
+
+static void pv_clock_wall(void)
+{
+    uint64_t wall = EMU_PA(&shared_info.wc_version);
+
+    printk(1, "%s: register wall clock at 0x%" PRIx64 "\n",
+           __FUNCTION__, wall);
+
+    if (pv_have_clock) {
+        if (wrmsrl_safe(MSR_KVM_WALL_CLOCK, wall)) {
+            panic("MSR_KVM_WALL_CLOCK wrmsr failed", NULL);
+        }
+    } else {
+        shared_info.wc_version = 4;
+        shared_info.wc_sec = 0;
+        shared_info.wc_nsec = 0;
+    }
+
+    printk(1, "%s: v%d %d.%09d\n", __FUNCTION__,
+           shared_info.wc_version,
+           shared_info.wc_sec,
+           shared_info.wc_nsec);
+}
+
+void pv_clock_sys(struct xen_cpu *cpu)
+{
+    uint64_t sys = cpu->v.vcpu_info_pa + offsetof(struct vcpu_info, time);
+
+    printk(1, "%s: register vcpu %d clock at 0x%" PRIx64 "\n",
+           __FUNCTION__, cpu->id, sys);
+
+    if (pv_have_clock) {
+        if (wrmsrl_safe(MSR_KVM_SYSTEM_TIME, sys | 1)) {
+            panic("MSR_KVM_SYSTEM_TIME wrmsr failed", NULL);
+        }
+    } else {
+        /* fake data */
+        cpu->v.vcpu_info->time.tsc_to_system_mul = 1;
+        cpu->v.vcpu_info->time.version = 2;
+        cpu->v.vcpu_info->time.tsc_timestamp = rdtsc();
+        cpu->v.vcpu_info->time.system_time =
+            cpu->v.vcpu_info->time.tsc_timestamp;
+        cpu->v.vcpu_info->time.tsc_shift = 0;
+    }
+
+    printk(1, "%s: v%d sys %" PRIu64 " tsc %" PRIu64 " mul %u shift %d\n",
+           __FUNCTION__,
+           cpu->v.vcpu_info->time.version,
+           cpu->v.vcpu_info->time.system_time,
+           cpu->v.vcpu_info->time.tsc_timestamp,
+           cpu->v.vcpu_info->time.tsc_to_system_mul,
+           cpu->v.vcpu_info->time.tsc_shift);
+}
+
+/* --------------------------------------------------------------------- */
+
+void pv_write_cr3(struct xen_cpu *cpu, ureg_t cr3_mfn)
+{
+    ureg_t cr3 = frame_to_addr(cr3_mfn);
+
+#ifdef CONFIG_64BIT
+    if (cpu->user_mode) {
+        cpu->user_cr3_mfn = cr3_mfn;
+    } else {
+        cpu->kernel_cr3_mfn = cr3_mfn;
+    }
+#else
+    cpu->cr3_mfn = cr3_mfn;
+#endif
+
+    vminfo.faults[XEN_FAULT_OTHER_CR3_LOAD]++;
+    write_cr3(cr3);
+    return;
+}
+
+/* --------------------------------------------------------------------- */
+
+void pv_init(struct xen_cpu *cpu)
+{
+    char buf[128];
+    struct kvm_cpuid_entry entry;
+    uint32_t sig[3];
+    uint32_t features;
+
+    entry.function = KVM_CPUID_SIGNATURE;
+    real_cpuid(&entry);
+    sig[0] = entry.ebx;
+    sig[1] = entry.ecx;
+    sig[2] = entry.edx;
+    if (0 != memcmp((char*)sig, "KVMKVMKVM", 10)) {
+        printk(1, "%s: no kvm signature: \"%.12s\"\n",
+               __FUNCTION__, (char*)sig);
+        goto no_kvm;
+    }
+
+    entry.function = KVM_CPUID_FEATURES;
+    real_cpuid(&entry);
+    features = entry.eax;
+
+    snprintf(buf, sizeof(buf), "%s: cpu %d, signature \"%.12s\", features 0x%08x",
+             __FUNCTION__, cpu->id, (char*)sig, features);
+    print_bits(1, buf, features, features, feature_bits);
+
+    /* pv clocksource */
+    if (features & (1 << KVM_FEATURE_CLOCKSOURCE)) {
+        pv_have_clock = 1;
+    }
+
+no_kvm:
+    pv_clock_sys(cpu);
+    if (cpu->id == 0) {
+       pv_clock_wall();
+    }
+}
+
+/* --------------------------------------------------------------------- */
+
-- 
1.6.0.2