Commit f422f853 authored by Paul Durrant's avatar Paul Durrant Committed by Sean Christopherson
Browse files

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: default avatarPaul Durrant <pdurrant@amazon.com>
Reviewed-by: default avatarDavid Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/20230106103600.528-3-pdurrant@amazon.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 48639df8

arch/x86/include/asm/kvm_host.h

+1 −0
Original line number Diff line number Diff line
@@ -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 {

arch/x86/include/asm/xen/hypervisor.h

+3 −1
Original line number Diff line number Diff line
@@ -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;

arch/x86/kvm/cpuid.c

+2 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#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
@@ -443,6 +444,7 @@ 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;

arch/x86/kvm/x86.c

+1 −0
Original line number Diff line number Diff line
@@ -3161,6 +3161,7 @@ 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;

arch/x86/kvm/xen.c

+26 −0
Original line number Diff line number Diff line
@@ -23,6 +23,9 @@ 
#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);
@@ -2077,6 +2080,29 @@ 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)

{

	mutex_init(&kvm->arch.xen.xen_lock);