KVM: nVMX: fixes for preemption timer migration

Commit 850448f35aaf ("KVM: nVMX: Fix VMX preemption timer migration",
2020-06-01) accidentally broke nVMX live migration from older version
by changing the userspace ABI.  Restore it and, while at it, ensure
that vmx->nested.has_preemption_timer_deadline is always initialized
according to the KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE flag.

Cc: Makarand Sonare <makarandsonare@google.com>
Fixes: 850448f35aaf ("KVM: nVMX: Fix VMX preemption timer migration")
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 426f94582b7a1a58a21e7e703beb3bc052440f90..320788f81a051ac8db3703a2e791ff8879d05915 100644 (file)
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -4339,14 +4339,15 @@ Errors:
 #define KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE 0x00000001
 
   struct kvm_vmx_nested_state_hdr {
-       __u32 flags;
        __u64 vmxon_pa;
        __u64 vmcs12_pa;
-       __u64 preemption_timer_deadline;
 
        struct {
                __u16 flags;
        } smm;
+
+       __u32 flags;
+       __u64 preemption_timer_deadline;
   };
 
   struct kvm_vmx_nested_state_data {

diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
index 17c5a038f42d3978d1b06d7cec5f8c8afd92eaaf..0780f97c185088ce214bf7f57d917fda7aff730b 100644 (file)
--- a/arch/x86/include/uapi/asm/kvm.h
+++ b/arch/x86/include/uapi/asm/kvm.h
@@ -408,14 +408,15 @@ struct kvm_vmx_nested_state_data {
 };
 
 struct kvm_vmx_nested_state_hdr {
-       __u32 flags;
        __u64 vmxon_pa;
        __u64 vmcs12_pa;
-       __u64 preemption_timer_deadline;
 
        struct {
                __u16 flags;
        } smm;
+
+       __u32 flags;
+       __u64 preemption_timer_deadline;
 };
 
 struct kvm_svm_nested_state_data {

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index b26655104d4a9ccf8ceae2f5185df376b8fa38a3..d4a4cec034d00bf7ee4b7afb1703c40a0b7c7b54 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -6176,6 +6176,7 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
                        goto error_guest_mode;
        }
 
+       vmx->nested.has_preemption_timer_deadline = false;
        if (kvm_state->hdr.vmx.flags & KVM_STATE_VMX_PREEMPTION_TIMER_DEADLINE) {
                vmx->nested.has_preemption_timer_deadline = true;
                vmx->nested.preemption_timer_deadline =