4.19-stable review patch. If anyone has any objections, please let me know.
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From: Leonid Shatz leonid.shatz@oracle.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@oracle.com Reviewed-by: Mihai Carabas mihai.carabas@oracle.com Reviewed-by: Krish Sadhukhan krish.sadhukhan@oracle.com Signed-off-by: Leonid Shatz leonid.shatz@oracle.com Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.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)