linux-kernel - [RFC: timer passthrough 7/9] KVM: vmx: save the initial value of host tscd

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Message-Id: <20210205100317.24174-8-fengzhimin@bytedance.com>
Date:   Fri,  5 Feb 2021 18:03:15 +0800
From:   Zhimin Feng <fengzhimin@...edance.com>
To:     x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     pbonzini@...hat.com, seanjc@...gle.com, vkuznets@...hat.com,
        wanpengli@...cent.com, jmattson@...gle.com, joro@...tes.org,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
        fweisbec@...il.com, zhouyibo@...edance.com,
        zhanghaozhong@...edance.com, Zhimin Feng <fengzhimin@...edance.com>
Subject: [RFC: timer passthrough 7/9] KVM: vmx: save the initial value of host tscd

Record the host tscd value.

Signed-off-by: Zhimin Feng <fengzhimin@...edance.com>
---
 arch/x86/kvm/vmx/vmx.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index a12da3cef86d..98eca70d4251 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -251,8 +251,11 @@ static void vmx_host_timer_passth_init(void *junk)
 {
 	struct timer_passth_info *local_timer_info;
 	int cpu = smp_processor_id();
+	u64 tscd;
 
 	local_timer_info = &per_cpu(passth_info, cpu);
+	rdmsrl(MSR_IA32_TSC_DEADLINE, tscd);
+	local_timer_info->host_tscd = tscd;
 	local_timer_info->curr_dev = per_cpu(tick_cpu_device, cpu).evtdev;
 	local_timer_info->orig_set_next_event =
 		local_timer_info->curr_dev->set_next_event;
@@ -266,6 +269,7 @@ static void vmx_host_timer_restore(void *junk)
 	local_timer_info = &per_cpu(passth_info, smp_processor_id());
 	local_timer_info->curr_dev->set_next_event =
 		local_timer_info->orig_set_next_event;
+	local_timer_info->host_tscd = 0;
 }
 
 #define L1D_CACHE_ORDER 4
-- 
2.11.0