linux-kernel - [PATCH 09/10] KVM: x86: Setup Hyper-V TSC page before Xen PV clocks (during clock update)

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Message-ID: <20250118005552.2626804-10-seanjc@google.com>
Date: Fri, 17 Jan 2025 16:55:51 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>, 
	David Woodhouse <dwmw2@...radead.org>, Paul Durrant <paul@....org>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	syzbot+352e553a86e0d75f5120@...kaller.appspotmail.com, 
	Paul Durrant <pdurrant@...zon.com>, David Woodhouse <dwmw@...zon.co.uk>, 
	Vitaly Kuznetsov <vkuznets@...hat.com>
Subject: [PATCH 09/10] KVM: x86: Setup Hyper-V TSC page before Xen PV clocks
 (during clock update)

When updating paravirtual clocks, setup the Hyper-V TSC page before
Xen PV clocks.  This will allow dropping xen_pvclock_tsc_unstable in favor
of simply clearing PVCLOCK_TSC_STABLE_BIT in the reference flags.

Cc: Vitaly Kuznetsov <vkuznets@...hat.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/x86.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9eabd70891dd..c68e7f7ba69d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3280,6 +3280,8 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
 		hv_clock.flags &= ~PVCLOCK_GUEST_STOPPED;
 	}
 
+	kvm_hv_setup_tsc_page(v->kvm, &hv_clock);
+
 #ifdef CONFIG_KVM_XEN
 	if (vcpu->xen.vcpu_info_cache.active)
 		kvm_setup_guest_pvclock(&hv_clock, v, &vcpu->xen.vcpu_info_cache,
@@ -3289,7 +3291,6 @@ static int kvm_guest_time_update(struct kvm_vcpu *v)
 		kvm_setup_guest_pvclock(&hv_clock, v, &vcpu->xen.vcpu_time_info_cache, 0,
 					xen_pvclock_tsc_unstable);
 #endif
-	kvm_hv_setup_tsc_page(v->kvm, &hv_clock);
 	return 0;
 }
 
-- 
2.48.0.rc2.279.g1de40edade-goog