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Message-ID: <20250314183422.2990277-2-pbonzini@redhat.com>
Date: Fri, 14 Mar 2025 14:34:21 -0400
From: Paolo Bonzini <pbonzini@...hat.com>
To: linux-kernel@...r.kernel.org,
kvm@...r.kernel.org
Cc: isaku.yamahata@...el.com,
nikunj@....com
Subject: [PATCH v2 1/2] KVM: x86: Push down setting vcpu.arch.user_set_tsc
From: Isaku Yamahata <isaku.yamahata@...el.com>
Push down setting vcpu.arch.user_set_tsc to true from kvm_synchronize_tsc()
to __kvm_synchronize_tsc() so that the two callers don't have to modify
user_set_tsc directly as preparation.
Later, prohibit changing TSC synchronization for TDX guests to modify
__kvm_synchornize_tsc() change. We don't want to touch caller sites not to
change user_set_tsc.
Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
Message-ID: <62b1a7a35d6961844786b6e47e8ecb774af7a228.1728719037.git.isaku.yamahata@...el.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
arch/x86/kvm/x86.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bd2b71d4e64f..2da75bbf7f94 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2626,12 +2626,15 @@ static inline bool kvm_check_tsc_unstable(void)
* participates in.
*/
static void __kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 offset, u64 tsc,
- u64 ns, bool matched)
+ u64 ns, bool matched, bool user_set_tsc)
{
struct kvm *kvm = vcpu->kvm;
lockdep_assert_held(&kvm->arch.tsc_write_lock);
+ if (user_set_tsc)
+ vcpu->kvm->arch.user_set_tsc = true;
+
/*
* We also track th most recent recorded KHZ, write and time to
* allow the matching interval to be extended at each write.
@@ -2717,8 +2720,6 @@ static void kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 *user_value)
}
}
- if (user_value)
- kvm->arch.user_set_tsc = true;
/*
* For a reliable TSC, we can match TSC offsets, and for an unstable
@@ -2738,7 +2739,7 @@ static void kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 *user_value)
matched = true;
}
- __kvm_synchronize_tsc(vcpu, offset, data, ns, matched);
+ __kvm_synchronize_tsc(vcpu, offset, data, ns, matched, !!user_value);
raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);
}
@@ -5725,8 +5726,7 @@ static int kvm_arch_tsc_set_attr(struct kvm_vcpu *vcpu,
tsc = kvm_scale_tsc(rdtsc(), vcpu->arch.l1_tsc_scaling_ratio) + offset;
ns = get_kvmclock_base_ns();
- kvm->arch.user_set_tsc = true;
- __kvm_synchronize_tsc(vcpu, offset, tsc, ns, matched);
+ __kvm_synchronize_tsc(vcpu, offset, tsc, ns, matched, true);
raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags);
r = 0;
--
2.43.5
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