[src/trunk]: src/sys/dev/nvmm/x86 nvmm-x86-svm: improve the CPUID emulation

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

details:   https://anonhg.NetBSD.org/src/rev/316adc2219ee
branches:  trunk
changeset: 974972:316adc2219ee
user:      maxv <maxv%NetBSD.org@localhost>
date:      Tue Aug 18 17:08:05 2020 +0000

description:
nvmm-x86-svm: improve the CPUID emulation

Limit the hypervisor range, and properly handle each basic leaf until 0xD.

diffstat:

 sys/dev/nvmm/x86/nvmm_x86_svm.c |  54 ++++++++++++++++++++++++++++++++++++----
 1 files changed, 48 insertions(+), 6 deletions(-)

diffs (98 lines):

diff -r 8476209897b1 -r 316adc2219ee sys/dev/nvmm/x86/nvmm_x86_svm.c
--- a/sys/dev/nvmm/x86/nvmm_x86_svm.c   Tue Aug 18 17:04:37 2020 +0000
+++ b/sys/dev/nvmm/x86/nvmm_x86_svm.c   Tue Aug 18 17:08:05 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: nvmm_x86_svm.c,v 1.68 2020/08/18 17:03:10 maxv Exp $   */
+/*     $NetBSD: nvmm_x86_svm.c,v 1.69 2020/08/18 17:08:05 maxv Exp $   */
 
 /*
  * Copyright (c) 2018-2020 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nvmm_x86_svm.c,v 1.68 2020/08/18 17:03:10 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nvmm_x86_svm.c,v 1.69 2020/08/18 17:08:05 maxv Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -793,7 +793,21 @@
        vmcb->ctrl.intr &= ~VMCB_CTRL_INTR_SHADOW;
 }
 
+#define SVM_CPUID_MAX_BASIC            0xD
 #define SVM_CPUID_MAX_HYPERVISOR       0x40000000
+static uint32_t svm_cpuid_max_basic __read_mostly;
+
+static void
+svm_inkernel_exec_cpuid(struct svm_cpudata *cpudata, uint64_t eax, uint64_t ecx)
+{
+       u_int descs[4];
+
+       x86_cpuid2(eax, ecx, descs);
+       cpudata->vmcb->state.rax = descs[0];
+       cpudata->gprs[NVMM_X64_GPR_RBX] = descs[1];
+       cpudata->gprs[NVMM_X64_GPR_RCX] = descs[2];
+       cpudata->gprs[NVMM_X64_GPR_RDX] = descs[3];
+}
 
 static void
 svm_inkernel_handle_cpuid(struct nvmm_cpu *vcpu, uint64_t eax, uint64_t ecx)
@@ -801,7 +815,22 @@
        struct svm_cpudata *cpudata = vcpu->cpudata;
        uint64_t cr4;
 
+       if (eax < 0x40000000) {
+               if (__predict_false(eax > svm_cpuid_max_basic)) {
+                       eax = svm_cpuid_max_basic;
+                       svm_inkernel_exec_cpuid(cpudata, eax, ecx);
+               }
+       } else if (eax < 0x80000000) {
+               if (__predict_false(eax > SVM_CPUID_MAX_HYPERVISOR)) {
+                       eax = svm_cpuid_max_basic;
+                       svm_inkernel_exec_cpuid(cpudata, eax, ecx);
+               }
+       }
+
        switch (eax) {
+       case 0x00000000:
+               cpudata->vmcb->state.rax = svm_cpuid_max_basic;
+               break;
        case 0x00000001:
                cpudata->vmcb->state.rax &= nvmm_cpuid_00000001.eax;
 
@@ -831,10 +860,20 @@
                cpudata->gprs[NVMM_X64_GPR_RDX] = 0;
                break;
        case 0x00000007: /* Structured Extended Features */
-               cpudata->vmcb->state.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;
+               switch (ecx) {
+               case 0:
+                       cpudata->vmcb->state.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;
+                       break;
+               default:
+                       cpudata->vmcb->state.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 */
        case 0x00000009: /* Empty */
@@ -2418,6 +2457,9 @@
        /* Init the XCR0 mask. */
        svm_xcr0_mask = SVM_XCR0_MASK_DEFAULT & x86_xsave_features;
 
+       /* Init the max basic CPUID leaf. */
+       svm_cpuid_max_basic = uimin(cpuid_level, SVM_CPUID_MAX_BASIC);
+
        memset(hsave, 0, sizeof(hsave));
        for (CPU_INFO_FOREACH(cii, ci)) {
                pg = uvm_pagealloc(NULL, 0, NULL, UVM_PGA_ZERO);