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Message-Id: <20230106103600.528-3-pdurrant@amazon.com>
Date: Fri, 6 Jan 2023 10:36:00 +0000
From: Paul Durrant <pdurrant@...zon.com>
To: x86@...nel.org, kvm@...r.kernel.org,
xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org
Cc: Paul Durrant <pdurrant@...zon.com>,
Sean Christopherson <seanjc@...gle.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Juergen Gross <jgross@...e.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
"H. Peter Anvin" <hpa@...or.com>,
David Woodhouse <dwmw2@...radead.org>
Subject: [PATCH v7 2/2] KVM: x86/xen: update Xen CPUID Leaf 4 (tsc info) sub-leaves, if present
The scaling information in subleaf 1 should match the values set by KVM in
the 'vcpu_info' sub-structure 'time_info' (a.k.a. pvclock_vcpu_time_info)
which is shared with the guest, but is not directly available to the VMM.
The offset values are not set since a TSC offset is already applied.
The TSC frequency should also be set in sub-leaf 2.
Signed-off-by: Paul Durrant <pdurrant@...zon.com>
---
Cc: Sean Christopherson <seanjc@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Juergen Gross <jgross@...e.com>
Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: David Woodhouse <dwmw2@...radead.org>
v7:
- Add a definition of XEN_SIGNATURE into asm/xen/hypervisor.h
and use that
v6:
- Stash Xen cpuid base and limit values when cpuid is set
- Re-name kvm_xen_setup_tsc_info() to kvm_xen_update_tsc_info()
v5:
- Drop the caching of the CPUID entry pointers and only update the
sub-leaves if the CPU frequency has actually changed
v4:
- Update commit comment
v3:
- Add leaf limit check in kvm_xen_set_cpuid()
v2:
- Make sure sub-leaf pointers are NULLed if the time leaf is removed
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/include/asm/xen/hypervisor.h | 4 +++-
arch/x86/kvm/cpuid.c | 2 ++
arch/x86/kvm/x86.c | 1 +
arch/x86/kvm/xen.c | 26 ++++++++++++++++++++++++++
arch/x86/kvm/xen.h | 7 +++++++
6 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 85cbe4571ac9..f3e9f6e4b3ea 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -703,6 +703,7 @@ struct kvm_vcpu_xen {
struct hrtimer timer;
int poll_evtchn;
struct timer_list poll_timer;
+ struct kvm_hypervisor_cpuid cpuid;
};
struct kvm_queued_exception {
diff --git a/arch/x86/include/asm/xen/hypervisor.h b/arch/x86/include/asm/xen/hypervisor.h
index 16f548a661cf..5fc35f889cd1 100644
--- a/arch/x86/include/asm/xen/hypervisor.h
+++ b/arch/x86/include/asm/xen/hypervisor.h
@@ -38,9 +38,11 @@ extern struct start_info *xen_start_info;
#include <asm/processor.h>
+#define XEN_SIGNATURE "XenVMMXenVMM"
+
static inline uint32_t xen_cpuid_base(void)
{
- return hypervisor_cpuid_base("XenVMMXenVMM", 2);
+ return hypervisor_cpuid_base(XEN_SIGNATURE, 2);
}
struct pci_dev;
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index db5a4d38fcd0..560f880cc9fd 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -25,6 +25,7 @@
#include "mmu.h"
#include "trace.h"
#include "pmu.h"
+#include "xen.h"
/*
* Unlike "struct cpuinfo_x86.x86_capability", kvm_cpu_caps doesn't need to be
@@ -442,6 +443,7 @@ static int kvm_set_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *e2,
vcpu->arch.cpuid_nent = nent;
vcpu->arch.kvm_cpuid = kvm_get_hypervisor_cpuid(vcpu, KVM_SIGNATURE);
+ vcpu->arch.xen.cpuid = kvm_get_hypervisor_cpuid(vcpu, XEN_SIGNATURE);
kvm_vcpu_after_set_cpuid(vcpu);
return 0;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index f6ef44dc8a0e..e849a5445cac 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3158,6 +3158,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
&vcpu->hv_clock.tsc_shift,
&vcpu->hv_clock.tsc_to_system_mul);
vcpu->hw_tsc_khz = tgt_tsc_khz;
+ kvm_xen_update_tsc_info(v);
}
vcpu->hv_clock.tsc_timestamp = tsc_timestamp;
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 2e29bdc2949c..fbfc7c17defd 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -22,6 +22,9 @@
#include <xen/interface/event_channel.h>
#include <xen/interface/sched.h>
+#include <asm/xen/cpuid.h>
+
+#include "cpuid.h"
#include "trace.h"
static int kvm_xen_set_evtchn(struct kvm_xen_evtchn *xe, struct kvm *kvm);
@@ -2067,6 +2070,29 @@ void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu)
del_timer_sync(&vcpu->arch.xen.poll_timer);
}
+void kvm_xen_update_tsc_info(struct kvm_vcpu *vcpu)
+{
+ struct kvm_cpuid_entry2 *entry;
+ u32 function;
+
+ if (!vcpu->arch.xen.cpuid.base)
+ return;
+
+ function = vcpu->arch.xen.cpuid.base | XEN_CPUID_LEAF(3);
+ if (function > vcpu->arch.xen.cpuid.limit)
+ return;
+
+ entry = kvm_find_cpuid_entry_index(vcpu, function, 1);
+ if (entry) {
+ entry->ecx = vcpu->arch.hv_clock.tsc_to_system_mul;
+ entry->edx = vcpu->arch.hv_clock.tsc_shift;
+ }
+
+ entry = kvm_find_cpuid_entry_index(vcpu, function, 2);
+ if (entry)
+ entry->eax = vcpu->arch.hw_tsc_khz;
+}
+
void kvm_xen_init_vm(struct kvm *kvm)
{
idr_init(&kvm->arch.xen.evtchn_ports);
diff --git a/arch/x86/kvm/xen.h b/arch/x86/kvm/xen.h
index ea33d80a0c51..f8f1fe22d090 100644
--- a/arch/x86/kvm/xen.h
+++ b/arch/x86/kvm/xen.h
@@ -9,6 +9,8 @@
#ifndef __ARCH_X86_KVM_XEN_H__
#define __ARCH_X86_KVM_XEN_H__
+#include <asm/xen/hypervisor.h>
+
#ifdef CONFIG_KVM_XEN
#include <linux/jump_label_ratelimit.h>
@@ -32,6 +34,7 @@ int kvm_xen_set_evtchn_fast(struct kvm_xen_evtchn *xe,
int kvm_xen_setup_evtchn(struct kvm *kvm,
struct kvm_kernel_irq_routing_entry *e,
const struct kvm_irq_routing_entry *ue);
+void kvm_xen_update_tsc_info(struct kvm_vcpu *vcpu);
static inline bool kvm_xen_msr_enabled(struct kvm *kvm)
{
@@ -135,6 +138,10 @@ static inline bool kvm_xen_timer_enabled(struct kvm_vcpu *vcpu)
{
return false;
}
+
+static inline void kvm_xen_update_tsc_info(struct kvm_vcpu *vcpu)
+{
+}
#endif
int kvm_xen_hypercall(struct kvm_vcpu *vcpu);
--
2.20.1
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