I noticed this while Hans-Joerg was working on SEV support for
vmm(4). Since vpid allocation is in the reset register ioctl handler,
and we don't free any previous vpid, a program on an Intel host that
keeps resetting a vcpu via VMM_IOC_RESETCPU will exhaust vpids.

Instead of a check & free dance, this just moves the allocation to the
vcpu initialization since vmm frees vpids/asids in vcpu de-init. (The
SEV changes moved the SVM ASID stuff similarly.)

It also removes the DPRINTF (also on the SVM side) since the allocation
function already has a printf on failure.

Plus, since we're de-coupling allocation from configuration, the VMCS
reload can be avoided, making this a net-negative diff.

ok?


diffstat refs/heads/master refs/heads/vpid-leak
 M  sys/arch/amd64/amd64/vmm_machdep.c  |  7+  21-

1 file changed, 7 insertions(+), 21 deletions(-)

diff refs/heads/master refs/heads/vpid-leak
commit - 24056440d1d6e8d3aa8785990526387386042fb4
commit + a01d423d1b92501a0e6b5cc4b9fe22a9e3983795
blob - c84fbb3273c799116e4628a1097db4eb9f135955
blob + a472790c5d18da3cc8c7954a2c5006b745009c53
--- sys/arch/amd64/amd64/vmm_machdep.c
+++ sys/arch/amd64/amd64/vmm_machdep.c
@@ -2253,7 +2253,7 @@ vcpu_reset_regs_vmx(struct vcpu *vcpu, struct vcpu_reg
 	uint32_t pinbased, procbased, procbased2, exit, entry;
 	uint32_t want1, want0;
 	uint64_t ctrlval, cr3, msr_misc_enable;
-	uint16_t ctrl, vpid;
+	uint16_t ctrl;
 	struct vmx_msr_store *msr_store;

 	rw_assert_wrlock(&vcpu->vc_lock);
@@ -2516,30 +2516,12 @@ vcpu_reset_regs_vmx(struct vcpu *vcpu, struct vcpu_reg
 	    IA32_VMX_ACTIVATE_SECONDARY_CONTROLS, 1)) {
 		if (vcpu_vmx_check_cap(vcpu, IA32_VMX_PROCBASED2_CTLS,
 		    IA32_VMX_ENABLE_VPID, 1)) {
-
-			/* We may sleep during allocation, so reload VMCS. */
-			vcpu->vc_last_pcpu = curcpu();
-			ret = vmm_alloc_vpid(&vpid);
-			if (vcpu_reload_vmcs_vmx(vcpu)) {
-				printf("%s: failed to reload vmcs\n", __func__);
-				ret = EINVAL;
-				goto exit;
-			}
-			if (ret) {
-				DPRINTF("%s: could not allocate VPID\n",
-				    __func__);
-				ret = EINVAL;
-				goto exit;
-			}
-
-			if (vmwrite(VMCS_GUEST_VPID, vpid)) {
+			if (vmwrite(VMCS_GUEST_VPID, vcpu->vc_vpid)) {
 				DPRINTF("%s: error setting guest VPID\n",
 				    __func__);
 				ret = EINVAL;
 				goto exit;
 			}
-
-			vcpu->vc_vpid = vpid;
 		}
 	}

@@ -2832,6 +2814,11 @@ vcpu_init_vmx(struct vcpu *vcpu)
 	uint32_t cr0, cr4;
 	int ret = 0;

+	/* Allocate a VPID early because there's no cleanup to do on failure. */
+	ret = vmm_alloc_vpid(&vcpu->vc_vpid);
+	if (ret)
+		return (ret);
+
 	/* Allocate VMCS VA */
 	vcpu->vc_control_va = (vaddr_t)km_alloc(PAGE_SIZE, &kv_page, &kp_zero,
 	    &kd_waitok);
@@ -3175,7 +3162,6 @@ vcpu_init_svm(struct vcpu *vcpu, struct vm_create_para

 	/* Guest VCPU ASID */
 	if (vmm_alloc_vpid(&asid)) {
-		DPRINTF("%s: could not allocate asid\n", __func__);
 		ret = EINVAL;
 		goto exit;
 	}