KVM: VMX: Initialize vm86 TSS only once.
Currently vm86 task is initialized on each real mode entry and vcpu
reset. Initialization is done by zeroing TSS and updating relevant
fields. But since all vcpus are using the same TSS there is a race where
one vcpu may use TSS while other vcpu is initializing it, so the vcpu
that uses TSS will see wrong TSS content and will behave incorrectly.
Fix that by initializing TSS only once.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index dafb67e..e2b8c6b 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -176,7 +176,6 @@
return container_of(vcpu, struct vcpu_vmx, vcpu);
}
-static int init_rmode(struct kvm *kvm);
static u64 construct_eptp(unsigned long root_hpa);
static void kvm_cpu_vmxon(u64 addr);
static void kvm_cpu_vmxoff(void);
@@ -1802,7 +1801,6 @@
continue_rmode:
kvm_mmu_reset_context(vcpu);
- init_rmode(vcpu->kvm);
}
static void vmx_set_efer(struct kvm_vcpu *vcpu, u64 efer)
@@ -2737,22 +2735,6 @@
return 0;
}
-static int init_rmode(struct kvm *kvm)
-{
- int idx, ret = 0;
-
- idx = srcu_read_lock(&kvm->srcu);
- if (!init_rmode_tss(kvm))
- goto exit;
- if (!init_rmode_identity_map(kvm))
- goto exit;
-
- ret = 1;
-exit:
- srcu_read_unlock(&kvm->srcu, idx);
- return ret;
-}
-
static int vmx_vcpu_reset(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
@@ -2760,10 +2742,6 @@
int ret;
vcpu->arch.regs_avail = ~((1 << VCPU_REGS_RIP) | (1 << VCPU_REGS_RSP));
- if (!init_rmode(vmx->vcpu.kvm)) {
- ret = -ENOMEM;
- goto out;
- }
vmx->rmode.vm86_active = 0;
@@ -3009,6 +2987,9 @@
if (ret)
return ret;
kvm->arch.tss_addr = addr;
+ if (!init_rmode_tss(kvm))
+ return -ENOMEM;
+
return 0;
}
@@ -4224,8 +4205,11 @@
if (!kvm->arch.ept_identity_map_addr)
kvm->arch.ept_identity_map_addr =
VMX_EPT_IDENTITY_PAGETABLE_ADDR;
+ err = -ENOMEM;
if (alloc_identity_pagetable(kvm) != 0)
goto free_vmcs;
+ if (!init_rmode_identity_map(kvm))
+ goto free_vmcs;
}
return &vmx->vcpu;