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 <[email protected]> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index e2b8c6b..280b6ea 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 +1763,16 @@ 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"); + vmx_set_tss_addr(vcpu->kvm, 0xfeffd000); + } + 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)); -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
