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authorGleb Natapov <gleb@redhat.com>2011-03-13 12:34:27 +0200
committerMarcelo Tosatti <mtosatti@redhat.com>2011-03-17 13:08:35 -0300
commit776e58ea3d3735f85678155398241d2513afa67a (patch)
tree7c723831868e25084707096b24a0e692abb87a5b /arch
parent0f53b5b1c0baae4f949ac0721a55b7a2158dda01 (diff)
KVM: unbreak userspace that does not sets tss address
Commit 6440e5967bc broke old userspaces that do not set tss address before entering vcpu. Unbreak it by setting tss address to a safe value on the first vcpu entry. New userspaces should set tss address, so print warning in case it doesn't. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/vmx.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d8475a26add6..5b4cdcbd154c 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -180,6 +180,7 @@ static u64 construct_eptp(unsigned long root_hpa);
static void kvm_cpu_vmxon(u64 addr);
static void kvm_cpu_vmxoff(void);
static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3);
+static int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr);
static DEFINE_PER_CPU(struct vmcs *, vmxarea);
static DEFINE_PER_CPU(struct vmcs *, current_vmcs);
@@ -1762,6 +1763,18 @@ static void enter_rmode(struct kvm_vcpu *vcpu)
vmx->emulation_required = 1;
vmx->rmode.vm86_active = 1;
+ /*
+ * Very old userspace does not call KVM_SET_TSS_ADDR before entering
+ * vcpu. Call it here with phys address pointing 16M below 4G.
+ */
+ if (!vcpu->kvm->arch.tss_addr) {
+ printk_once(KERN_WARNING "kvm: KVM_SET_TSS_ADDR need to be "
+ "called before entering vcpu\n");
+ srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
+ vmx_set_tss_addr(vcpu->kvm, 0xfeffd000);
+ vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+ }
+
vmx->rmode.tr.selector = vmcs_read16(GUEST_TR_SELECTOR);
vmx->rmode.tr.base = vmcs_readl(GUEST_TR_BASE);
vmcs_writel(GUEST_TR_BASE, rmode_tss_base(vcpu->kvm));