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Message-Id: <20181204103652.702958456@linuxfoundation.org>
Date: Tue, 4 Dec 2018 11:49:06 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Liran Alon <liran.alon@...cle.com>,
Mihai Carabas <mihai.carabas@...cle.com>,
Krish Sadhukhan <krish.sadhukhan@...cle.com>,
Leonid Shatz <leonid.shatz@...cle.com>,
Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 4.19 065/139] KVM: nVMX/nSVM: Fix bug which sets vcpu->arch.tsc_offset to L1 tsc_offset
4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Leonid Shatz <leonid.shatz@...cle.com>
commit 326e742533bf0a23f0127d8ea62fb558ba665f08 upstream.
Since commit e79f245ddec1 ("X86/KVM: Properly update 'tsc_offset' to
represent the running guest"), vcpu->arch.tsc_offset meaning was
changed to always reflect the tsc_offset value set on active VMCS.
Regardless if vCPU is currently running L1 or L2.
However, above mentioned commit failed to also change
kvm_vcpu_write_tsc_offset() to set vcpu->arch.tsc_offset correctly.
This is because vmx_write_tsc_offset() could set the tsc_offset value
in active VMCS to given offset parameter *plus vmcs12->tsc_offset*.
However, kvm_vcpu_write_tsc_offset() just sets vcpu->arch.tsc_offset
to given offset parameter. Without taking into account the possible
addition of vmcs12->tsc_offset. (Same is true for SVM case).
Fix this issue by changing kvm_x86_ops->write_tsc_offset() to return
actually set tsc_offset in active VMCS and modify
kvm_vcpu_write_tsc_offset() to set returned value in
vcpu->arch.tsc_offset.
In addition, rename write_tsc_offset() callback to write_l1_tsc_offset()
to make it clear that it is meant to set L1 TSC offset.
Fixes: e79f245ddec1 ("X86/KVM: Properly update 'tsc_offset' to represent the running guest")
Reviewed-by: Liran Alon <liran.alon@...cle.com>
Reviewed-by: Mihai Carabas <mihai.carabas@...cle.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@...cle.com>
Signed-off-by: Leonid Shatz <leonid.shatz@...cle.com>
Cc: stable@...r.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/x86/include/asm/kvm_host.h | 3 ++-
arch/x86/kvm/svm.c | 5 +++--
arch/x86/kvm/vmx.c | 21 +++++++++------------
arch/x86/kvm/x86.c | 6 +++---
4 files changed, 17 insertions(+), 18 deletions(-)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1046,7 +1046,8 @@ struct kvm_x86_ops {
bool (*has_wbinvd_exit)(void);
u64 (*read_l1_tsc_offset)(struct kvm_vcpu *vcpu);
- void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);
+ /* Returns actual tsc_offset set in active VMCS */
+ u64 (*write_l1_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);
void (*get_exit_info)(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2);
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1444,7 +1444,7 @@ static u64 svm_read_l1_tsc_offset(struct
return vcpu->arch.tsc_offset;
}
-static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
+static u64 svm_write_l1_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
{
struct vcpu_svm *svm = to_svm(vcpu);
u64 g_tsc_offset = 0;
@@ -1462,6 +1462,7 @@ static void svm_write_tsc_offset(struct
svm->vmcb->control.tsc_offset = offset + g_tsc_offset;
mark_dirty(svm->vmcb, VMCB_INTERCEPTS);
+ return svm->vmcb->control.tsc_offset;
}
static void avic_init_vmcb(struct vcpu_svm *svm)
@@ -7155,7 +7156,7 @@ static struct kvm_x86_ops svm_x86_ops __
.has_wbinvd_exit = svm_has_wbinvd_exit,
.read_l1_tsc_offset = svm_read_l1_tsc_offset,
- .write_tsc_offset = svm_write_tsc_offset,
+ .write_l1_tsc_offset = svm_write_l1_tsc_offset,
.set_tdp_cr3 = set_tdp_cr3,
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3433,11 +3433,9 @@ static u64 vmx_read_l1_tsc_offset(struct
return vcpu->arch.tsc_offset;
}
-/*
- * writes 'offset' into guest's timestamp counter offset register
- */
-static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
+static u64 vmx_write_l1_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
{
+ u64 active_offset = offset;
if (is_guest_mode(vcpu)) {
/*
* We're here if L1 chose not to trap WRMSR to TSC. According
@@ -3445,17 +3443,16 @@ static void vmx_write_tsc_offset(struct
* set for L2 remains unchanged, and still needs to be added
* to the newly set TSC to get L2's TSC.
*/
- struct vmcs12 *vmcs12;
- /* recalculate vmcs02.TSC_OFFSET: */
- vmcs12 = get_vmcs12(vcpu);
- vmcs_write64(TSC_OFFSET, offset +
- (nested_cpu_has(vmcs12, CPU_BASED_USE_TSC_OFFSETING) ?
- vmcs12->tsc_offset : 0));
+ struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
+ if (nested_cpu_has(vmcs12, CPU_BASED_USE_TSC_OFFSETING))
+ active_offset += vmcs12->tsc_offset;
} else {
trace_kvm_write_tsc_offset(vcpu->vcpu_id,
vmcs_read64(TSC_OFFSET), offset);
- vmcs_write64(TSC_OFFSET, offset);
}
+
+ vmcs_write64(TSC_OFFSET, active_offset);
+ return active_offset;
}
/*
@@ -14203,7 +14200,7 @@ static struct kvm_x86_ops vmx_x86_ops __
.has_wbinvd_exit = cpu_has_vmx_wbinvd_exit,
.read_l1_tsc_offset = vmx_read_l1_tsc_offset,
- .write_tsc_offset = vmx_write_tsc_offset,
+ .write_l1_tsc_offset = vmx_write_l1_tsc_offset,
.set_tdp_cr3 = vmx_set_cr3,
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1582,8 +1582,7 @@ EXPORT_SYMBOL_GPL(kvm_read_l1_tsc);
static void kvm_vcpu_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
{
- kvm_x86_ops->write_tsc_offset(vcpu, offset);
- vcpu->arch.tsc_offset = offset;
+ vcpu->arch.tsc_offset = kvm_x86_ops->write_l1_tsc_offset(vcpu, offset);
}
static inline bool kvm_check_tsc_unstable(void)
@@ -1711,7 +1710,8 @@ EXPORT_SYMBOL_GPL(kvm_write_tsc);
static inline void adjust_tsc_offset_guest(struct kvm_vcpu *vcpu,
s64 adjustment)
{
- kvm_vcpu_write_tsc_offset(vcpu, vcpu->arch.tsc_offset + adjustment);
+ u64 tsc_offset = kvm_x86_ops->read_l1_tsc_offset(vcpu);
+ kvm_vcpu_write_tsc_offset(vcpu, tsc_offset + adjustment);
}
static inline void adjust_tsc_offset_host(struct kvm_vcpu *vcpu, s64 adjustment)
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