To implement steal time, we need the hypervisor to pass the guest information
about how much time was spent running other processes outside the VM.
This is per-vcpu, and using the kvmclock structure for that is an abuse
we decided not to make.
In this patchset, I am introducing a new msr, KVM_MSR_STEAL_TIME, that
holds the memory area address containing information about steal time
This patch contains the hypervisor part for it. I am keeping it separate from
the headers to facilitate backports to people who wants to backport the kernel
part but not the hypervisor, or the other way around.
Signed-off-by: Glauber Costa<glom...@redhat.com>
CC: Rik van Riel<r...@redhat.com>
CC: Jeremy Fitzhardinge<jeremy.fitzhardi...@citrix.com>
CC: Peter Zijlstra<pet...@infradead.org>
CC: Avi Kivity<a...@redhat.com>
CC: Anthony Liguori<aligu...@us.ibm.com>
CC: Eric B Munson<emun...@mgebm.net>
---
arch/x86/include/asm/kvm_host.h | 8 +++++
arch/x86/include/asm/kvm_para.h | 4 ++
arch/x86/kvm/x86.c | 60 +++++++++++++++++++++++++++++++++++++--
3 files changed, 69 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index fc38eca..5dce014 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -388,6 +388,14 @@ struct kvm_vcpu_arch {
unsigned int hw_tsc_khz;
unsigned int time_offset;
struct page *time_page;
+
+ struct {
+ u64 msr_val;
+ gpa_t stime;
+ struct kvm_steal_time steal;
+ u64 this_time_out;
+ } st;
+
u64 last_guest_tsc;
u64 last_kernel_ns;
u64 last_tsc_nsec;
diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index ac306c4..0341e61 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -45,6 +45,10 @@ struct kvm_steal_time {
__u32 pad[6];
};
+#define KVM_STEAL_ALIGNMENT_BITS 5
+#define KVM_STEAL_VALID_BITS ((-1ULL<< (KVM_STEAL_ALIGNMENT_BITS + 1)))
+#define KVM_STEAL_RESERVED_MASK (((1<< KVM_STEAL_ALIGNMENT_BITS) - 1 )<< 1)
+
#define KVM_MAX_MMU_OP_BATCH 32
#define KVM_ASYNC_PF_ENABLED (1<< 0)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6645634..10fe028 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -797,12 +797,12 @@ EXPORT_SYMBOL_GPL(kvm_get_dr);
* kvm-specific. Those are put in the beginning of the list.
*/
-#define KVM_SAVE_MSRS_BEGIN 8
+#define KVM_SAVE_MSRS_BEGIN 9
static u32 msrs_to_save[] = {
MSR_KVM_SYSTEM_TIME, MSR_KVM_WALL_CLOCK,
MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW,
HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL,
- HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN,
+ HV_X64_MSR_APIC_ASSIST_PAGE, MSR_KVM_ASYNC_PF_EN, MSR_KVM_STEAL_TIME,
MSR_IA32_SYSENTER_CS, MSR_IA32_SYSENTER_ESP, MSR_IA32_SYSENTER_EIP,
MSR_STAR,
#ifdef CONFIG_X86_64
@@ -1480,6 +1480,34 @@ static void kvmclock_reset(struct kvm_vcpu *vcpu)
}
}
+static void record_steal_time(struct kvm_vcpu *vcpu)
+{
+ u64 delta;
+
+ if (vcpu->arch.st.stime&& vcpu->arch.st.this_time_out) {
+
+ if (unlikely(kvm_read_guest(vcpu->kvm, vcpu->arch.st.stime,
+ &vcpu->arch.st.steal, sizeof(struct kvm_steal_time)))) {
+
+ vcpu->arch.st.stime = 0;
+ return;
+ }
+
+ delta = (get_kernel_ns() - vcpu->arch.st.this_time_out);
+
+ vcpu->arch.st.steal.steal += delta;
+ vcpu->arch.st.steal.version += 2;
+
+ if (unlikely(kvm_write_guest(vcpu->kvm, vcpu->arch.st.stime,
