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Subjectkvmclock - the host part.
Date
This is the host part of kvm clocksource implementation. As it does
not include clockevents, it is a fairly simple implementation. We
only have to register a per-vcpu area, and start writting to it periodically.

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
---
drivers/kvm/irq.c | 1 +
drivers/kvm/kvm_main.c | 2 +
drivers/kvm/svm.c | 1 +
drivers/kvm/vmx.c | 1 +
drivers/kvm/x86.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++
drivers/kvm/x86.h | 13 ++++++++++
6 files changed, 77 insertions(+), 0 deletions(-)

diff --git a/drivers/kvm/irq.c b/drivers/kvm/irq.c
index 22bfeee..0344879 100644
--- a/drivers/kvm/irq.c
+++ b/drivers/kvm/irq.c
@@ -92,6 +92,7 @@ void kvm_vcpu_kick_request(struct kvm_vcpu *vcpu, int request)

void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
{
+ vcpu->time_needs_update = 1;
kvm_inject_apic_timer_irqs(vcpu);
/* TODO: PIT, RTC etc. */
}
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 0b8edca..5834573 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -20,6 +20,7 @@
#include "x86_emulate.h"
#include "irq.h"

+#include <linux/clocksource.h>
#include <linux/kvm.h>
#include <linux/module.h>
#include <linux/errno.h>
@@ -1242,6 +1243,7 @@ static long kvm_dev_ioctl(struct file *filp,
case KVM_CAP_MMU_SHADOW_CACHE_CONTROL:
case KVM_CAP_USER_MEMORY:
case KVM_CAP_SET_TSS_ADDR:
+ case KVM_CAP_CLK:
r = 1;
break;
default:
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 95a3489..cb8c19d 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -617,6 +617,7 @@ static void svm_free_vcpu(struct kvm_vcpu *vcpu)

__free_page(pfn_to_page(svm->vmcb_pa >> PAGE_SHIFT));
kvm_vcpu_uninit(vcpu);
+ release_clock(vcpu);
kmem_cache_free(kvm_vcpu_cache, svm);
}

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index da3a339..b5edeed 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -2501,6 +2501,7 @@ static void vmx_free_vcpu(struct kvm_vcpu *vcpu)
kfree(vmx->host_msrs);
kfree(vmx->guest_msrs);
kvm_vcpu_uninit(vcpu);
+ release_clock(vcpu);
kmem_cache_free(kvm_vcpu_cache, vmx);
}

diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c
index e905d46..d476488 100644
--- a/drivers/kvm/x86.c
+++ b/drivers/kvm/x86.c
@@ -19,6 +19,7 @@
#include "segment_descriptor.h"
#include "irq.h"

+#include <linux/clocksource.h>
#include <linux/kvm.h>
#include <linux/fs.h>
#include <linux/vmalloc.h>
@@ -1628,6 +1629,31 @@ int kvm_emulate_halt(struct kvm_vcpu *vcpu)
}
EXPORT_SYMBOL_GPL(kvm_emulate_halt);

+static void kvm_write_guest_time(struct kvm_vcpu *vcpu)
+{
+ struct timespec ts;
+ void *clock_addr;
+
+
+ if (!vcpu->clock_page)
+ return;
+
+ /* Updates version to the next odd number, indicating we're writing */
+ vcpu->hv_clock.version++;
+ /* Updating the tsc count is the first thing we do */
+ kvm_get_msr(vcpu, MSR_IA32_TIME_STAMP_COUNTER, &vcpu->hv_clock.last_tsc);
+ ktime_get_ts(&ts);
+ vcpu->hv_clock.now_ns = ts.tv_nsec + (NSEC_PER_SEC * (u64)ts.tv_sec);
+ vcpu->hv_clock.wc_sec = get_seconds();
+ vcpu->hv_clock.version++;
+
+ clock_addr = vcpu->clock_addr;
+ memcpy(clock_addr, &vcpu->hv_clock, sizeof(vcpu->hv_clock));
+ mark_page_dirty(vcpu->kvm, vcpu->clock_gfn);
+
+ vcpu->time_needs_update = 0;
+}
+
int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
{
unsigned long nr, a0, a1, a2, a3, ret;
@@ -1648,7 +1674,33 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
a3 &= 0xFFFFFFFF;
}

+ ret = 0;
switch (nr) {
+ case KVM_HCALL_REGISTER_CLOCK: {
+ struct kvm_vcpu *dst_vcpu;
+
+ if (!((a1 < KVM_MAX_VCPUS) && (vcpu->kvm->vcpus[a1]))) {
+ ret = -KVM_EINVAL;
+ break;
+ }
+
+ dst_vcpu = vcpu->kvm->vcpus[a1];
+ dst_vcpu->clock_page = gfn_to_page(vcpu->kvm, a0 >> PAGE_SHIFT);
+
+ if (!dst_vcpu->clock_page) {
+ ret = -KVM_EINVAL;
+ break;
+ }
+ dst_vcpu->clock_gfn = a0 >> PAGE_SHIFT;
+
+ dst_vcpu->hv_clock.tsc_mult = clocksource_khz2mult(tsc_khz, 22);
+ dst_vcpu->clock_addr = kmap(dst_vcpu->clock_page);
+
+ dst_vcpu->time_needs_update = 1;
+
+ break;
+ }
+
default:
ret = -KVM_ENOSYS;
break;
@@ -1816,6 +1868,12 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu,
vcpu->irq_summary == 0);
}

+void kvm_update_guest_time(struct kvm_vcpu *vcpu)
+{
+ if (vcpu->time_needs_update)
+ kvm_write_guest_time(vcpu);
+}
+
static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
int r;
@@ -1876,6 +1934,7 @@ again:
vcpu->guest_mode = 1;
kvm_guest_enter();

+ kvm_update_guest_time(vcpu);
kvm_x86_ops->run(vcpu, kvm_run);

vcpu->guest_mode = 0;
diff --git a/drivers/kvm/x86.h b/drivers/kvm/x86.h
index 663b822..7a951cc 100644
--- a/drivers/kvm/x86.h
+++ b/drivers/kvm/x86.h
@@ -15,6 +15,7 @@

#include <linux/types.h>
#include <linux/mm.h>
+#include <linux/highmem.h>

#include <linux/kvm.h>
#include <linux/kvm_para.h>
@@ -83,8 +84,20 @@ struct kvm_vcpu {
/* emulate context */

struct x86_emulate_ctxt emulate_ctxt;
+
+ union kvm_hv_clock hv_clock;
+ int time_needs_update;
+ struct page *clock_page;
+ void *clock_addr; /* address in host space */
+ u64 clock_gfn; /* guest frame number, physical addr */
+
};

+static inline void release_clock(struct kvm_vcpu *vcpu)
+{
+ if (vcpu->clock_page)
+ kunmap(vcpu->clock_page);
+}
int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t gva, u32 error_code);

static inline void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu)
--
1.5.0.6
-
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