[src/trunk]: src/sys/dev/nvmm/x86 Improve the CPUID emulation on nvmm-intel:

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/32aa13692366
branches:  trunk
changeset: 1012833:32aa13692366
user:      maxv <maxv%NetBSD.org@localhost>
date:      Tue Aug 11 15:31:51 2020 +0000

description:
Improve the CPUID emulation on nvmm-intel:

 - Limit the highest extended leaf.
 - Limit 0x00000007 to ECX=0, for future-proofness.

diffstat:

 sys/dev/nvmm/x86/nvmm_x86_vmx.c |  42 ++++++++++++++++++++++++++++++++--------
 1 files changed, 33 insertions(+), 9 deletions(-)

diffs (100 lines):

diff -r 308d78dc03b4 -r 32aa13692366 sys/dev/nvmm/x86/nvmm_x86_vmx.c
--- a/sys/dev/nvmm/x86/nvmm_x86_vmx.c   Tue Aug 11 15:27:46 2020 +0000
+++ b/sys/dev/nvmm/x86/nvmm_x86_vmx.c   Tue Aug 11 15:31:51 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: nvmm_x86_vmx.c,v 1.68 2020/08/11 15:27:46 maxv Exp $   */
+/*     $NetBSD: nvmm_x86_vmx.c,v 1.69 2020/08/11 15:31:51 maxv Exp $   */
 
 /*
  * Copyright (c) 2018-2020 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nvmm_x86_vmx.c,v 1.68 2020/08/11 15:27:46 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nvmm_x86_vmx.c,v 1.69 2020/08/11 15:31:51 maxv Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1172,6 +1172,7 @@
 #define VMX_CPUID_MAX_HYPERVISOR       0x40000000
 #define VMX_CPUID_MAX_EXTENDED         0x80000008
 static uint32_t vmx_cpuid_max_basic __read_mostly;
+static uint32_t vmx_cpuid_max_extended __read_mostly;
 
 static void
 vmx_inkernel_exec_cpuid(struct vmx_cpudata *cpudata, uint64_t eax, uint64_t ecx)
@@ -1203,6 +1204,11 @@
                        eax = vmx_cpuid_max_basic;
                        vmx_inkernel_exec_cpuid(cpudata, eax, ecx);
                }
+       } else {
+               if (__predict_false(eax > vmx_cpuid_max_extended)) {
+                       eax = vmx_cpuid_max_basic;
+                       vmx_inkernel_exec_cpuid(cpudata, eax, ecx);
+               }
        }
 
        switch (eax) {
@@ -1248,12 +1254,22 @@
                cpudata->gprs[NVMM_X64_GPR_RDX] = 0;
                break;
        case 0x00000007: /* Structured Extended Feature Flags Enumeration */
-               cpudata->gprs[NVMM_X64_GPR_RAX] &= nvmm_cpuid_00000007.eax;
-               cpudata->gprs[NVMM_X64_GPR_RBX] &= nvmm_cpuid_00000007.ebx;
-               cpudata->gprs[NVMM_X64_GPR_RCX] &= nvmm_cpuid_00000007.ecx;
-               cpudata->gprs[NVMM_X64_GPR_RDX] &= nvmm_cpuid_00000007.edx;
-               if (vmx_procbased_ctls2 & PROC_CTLS2_INVPCID_ENABLE) {
-                       cpudata->gprs[NVMM_X64_GPR_RBX] |= CPUID_SEF_INVPCID;
+               switch (ecx) {
+               case 0:
+                       cpudata->gprs[NVMM_X64_GPR_RAX] = 0;
+                       cpudata->gprs[NVMM_X64_GPR_RBX] &= nvmm_cpuid_00000007.ebx;
+                       cpudata->gprs[NVMM_X64_GPR_RCX] &= nvmm_cpuid_00000007.ecx;
+                       cpudata->gprs[NVMM_X64_GPR_RDX] &= nvmm_cpuid_00000007.edx;
+                       if (vmx_procbased_ctls2 & PROC_CTLS2_INVPCID_ENABLE) {
+                               cpudata->gprs[NVMM_X64_GPR_RBX] |= CPUID_SEF_INVPCID;
+                       }
+                       break;
+               default:
+                       cpudata->gprs[NVMM_X64_GPR_RAX] = 0;
+                       cpudata->gprs[NVMM_X64_GPR_RBX] = 0;
+                       cpudata->gprs[NVMM_X64_GPR_RCX] = 0;
+                       cpudata->gprs[NVMM_X64_GPR_RDX] = 0;
+                       break;
                }
                break;
        case 0x00000008: /* Empty */
@@ -1365,6 +1381,9 @@
                memcpy(&cpudata->gprs[NVMM_X64_GPR_RDX], " ___", 4);
                break;
 
+       case 0x80000000:
+               cpudata->gprs[NVMM_X64_GPR_RAX] = vmx_cpuid_max_extended;
+               break;
        case 0x80000001:
                cpudata->gprs[NVMM_X64_GPR_RAX] &= nvmm_cpuid_80000001.eax;
                cpudata->gprs[NVMM_X64_GPR_RBX] &= nvmm_cpuid_80000001.ebx;
@@ -3346,6 +3365,7 @@
        uint64_t xc, msr;
        struct vmxon *vmxon;
        uint32_t revision;
+       u_int descs[4];
        paddr_t pa;
        vaddr_t va;
        int error;
@@ -3356,9 +3376,13 @@
        /* Init the XCR0 mask. */
        vmx_xcr0_mask = VMX_XCR0_MASK_DEFAULT & x86_xsave_features;
 
-       /* Init the max CPUID leaves. */
+       /* Init the max basic CPUID leaf. */
        vmx_cpuid_max_basic = uimin(cpuid_level, VMX_CPUID_MAX_BASIC);
 
+       /* Init the max extended CPUID leaf. */
+       x86_cpuid(0x80000000, descs);
+       vmx_cpuid_max_extended = uimin(descs[0], VMX_CPUID_MAX_EXTENDED);
+
        /* Init the TLB flush op, the EPT flush op and the EPTP type. */
        msr = rdmsr(MSR_IA32_VMX_EPT_VPID_CAP);
        if ((msr & IA32_VMX_EPT_VPID_INVVPID_CONTEXT) != 0) {