Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 776e58ea authored by Gleb Natapov's avatar Gleb Natapov Committed by Marcelo Tosatti
Browse files

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: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 0f53b5b1

arch/x86/kvm/vmx.c

+13 −0
Original line number Diff line number Diff line
@@ -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));