KVM: SVM: Add intercept check for emulated cr accesses
authorJoerg Roedel <joerg.roedel@amd.com>
Mon, 4 Apr 2011 10:39:28 +0000 (12:39 +0200)
committerAvi Kivity <avi@redhat.com>
Wed, 11 May 2011 11:57:01 +0000 (07:57 -0400)
This patch adds all necessary intercept checks for
instructions that access the crX registers.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
arch/x86/include/asm/kvm_emulate.h
arch/x86/include/asm/kvm_host.h
arch/x86/kvm/emulate.c
arch/x86/kvm/svm.c
arch/x86/kvm/x86.c

index eb7033cefe8ea4e22377b2144604f4e204154753..2c0b5b47464f167b54fa73957e256a7a6b02e9b3 100644 (file)
@@ -304,6 +304,9 @@ enum x86_intercept_stage {
 
 enum x86_intercept {
        x86_intercept_none,
+       x86_intercept_cr_read,
+       x86_intercept_cr_write,
+       x86_intercept_clts,
        x86_intercept_lmsw,
        x86_intercept_smsw,
        x86_intercept_lidt,
index 038562c222e843be415db324020d0c1c357ccccf..f7dfd6479d029ef6508ed4872315a0b6e01c6e4f 100644 (file)
 #define KVM_PIO_PAGE_OFFSET 1
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 2
 
+#define CR0_RESERVED_BITS                                               \
+       (~(unsigned long)(X86_CR0_PE | X86_CR0_MP | X86_CR0_EM | X86_CR0_TS \
+                         | X86_CR0_ET | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM \
+                         | X86_CR0_NW | X86_CR0_CD | X86_CR0_PG))
+
 #define CR3_PAE_RESERVED_BITS ((X86_CR3_PWT | X86_CR3_PCD) - 1)
 #define CR3_NONPAE_RESERVED_BITS ((PAGE_SIZE-1) & ~(X86_CR3_PWT | X86_CR3_PCD))
 #define CR3_L_MODE_RESERVED_BITS (CR3_NONPAE_RESERVED_BITS |   \
                                  0xFFFFFF0000000000ULL)
+#define CR4_RESERVED_BITS                                               \
+       (~(unsigned long)(X86_CR4_VME | X86_CR4_PVI | X86_CR4_TSD | X86_CR4_DE\
+                         | X86_CR4_PSE | X86_CR4_PAE | X86_CR4_MCE     \
+                         | X86_CR4_PGE | X86_CR4_PCE | X86_CR4_OSFXSR  \
+                         | X86_CR4_OSXSAVE \
+                         | X86_CR4_OSXMMEXCPT | X86_CR4_VMXE))
+
+#define CR8_RESERVED_BITS (~(unsigned long)X86_CR8_TPR)
+
+
 
 #define INVALID_PAGE (~(hpa_t)0)
 #define VALID_PAGE(x) ((x) != INVALID_PAGE)
index e3e96eada6f39ca00291134585db6afdedebeea4..d2e77755efe8a449502db9eff38b469466d1b63b 100644 (file)
@@ -2445,6 +2445,95 @@ static int em_movdqu(struct x86_emulate_ctxt *ctxt)
        return X86EMUL_CONTINUE;
 }
 
+static bool valid_cr(int nr)
+{
+       switch (nr) {
+       case 0:
+       case 2 ... 4:
+       case 8:
+               return true;
+       default:
+               return false;
+       }
+}
+
+static int check_cr_read(struct x86_emulate_ctxt *ctxt)
+{
+       struct decode_cache *c = &ctxt->decode;
+
+       if (!valid_cr(c->modrm_reg))
+               return emulate_ud(ctxt);
+
+       return X86EMUL_CONTINUE;
+}
+
+static int check_cr_write(struct x86_emulate_ctxt *ctxt)
+{
+       struct decode_cache *c = &ctxt->decode;
+       u64 new_val = c->src.val64;
+       int cr = c->modrm_reg;
+
+       static u64 cr_reserved_bits[] = {
+               0xffffffff00000000ULL,
+               0, 0, 0, /* CR3 checked later */
+               CR4_RESERVED_BITS,
+               0, 0, 0,
+               CR8_RESERVED_BITS,
+       };
+
+       if (!valid_cr(cr))
+               return emulate_ud(ctxt);
+
+       if (new_val & cr_reserved_bits[cr])
+               return emulate_gp(ctxt, 0);
+
+       switch (cr) {
+       case 0: {
+               u64 cr4, efer;
+               if (((new_val & X86_CR0_PG) && !(new_val & X86_CR0_PE)) ||
+                   ((new_val & X86_CR0_NW) && !(new_val & X86_CR0_CD)))
+                       return emulate_gp(ctxt, 0);
+
+               cr4 = ctxt->ops->get_cr(4, ctxt->vcpu);
+               ctxt->ops->get_msr(ctxt->vcpu, MSR_EFER, &efer);
+
+               if ((new_val & X86_CR0_PG) && (efer & EFER_LME) &&
+                   !(cr4 & X86_CR4_PAE))
+                       return emulate_gp(ctxt, 0);
+
+               break;
+               }
+       case 3: {
+               u64 rsvd = 0;
+
+               if (is_long_mode(ctxt->vcpu))
+                       rsvd = CR3_L_MODE_RESERVED_BITS;
+               else if (is_pae(ctxt->vcpu))
+                       rsvd = CR3_PAE_RESERVED_BITS;
+               else if (is_paging(ctxt->vcpu))
+                       rsvd = CR3_NONPAE_RESERVED_BITS;
+
+               if (new_val & rsvd)
+                       return emulate_gp(ctxt, 0);
+
+               break;
+               }
+       case 4: {
+               u64 cr4, efer;
+
+               cr4 = ctxt->ops->get_cr(4, ctxt->vcpu);
+               ctxt->ops->get_msr(ctxt->vcpu, MSR_EFER, &efer);
+
+               if ((efer & EFER_LMA) && !(new_val & X86_CR4_PAE))
+                       return emulate_gp(ctxt, 0);
+
+               break;
+               }
+       }
+
+       return X86EMUL_CONTINUE;
+}
+
 #define D(_y) { .flags = (_y) }
 #define DI(_y, _i) { .flags = (_y), .intercept = x86_intercept_##_i }
 #define DIP(_y, _i, _p) { .flags = (_y), .intercept = x86_intercept_##_i, \
@@ -2632,14 +2721,16 @@ static struct opcode opcode_table[256] = {
 static struct opcode twobyte_table[256] = {
        /* 0x00 - 0x0F */
        N, GD(0, &group7), N, N,
-       N, D(ImplicitOps | VendorSpecific), D(ImplicitOps | Priv), N,
+       N, D(ImplicitOps | VendorSpecific), DI(ImplicitOps | Priv, clts), N,
        DI(ImplicitOps | Priv, invd), DI(ImplicitOps | Priv, wbinvd), N, N,
        N, D(ImplicitOps | ModRM), N, N,
        /* 0x10 - 0x1F */
        N, N, N, N, N, N, N, N, D(ImplicitOps | ModRM), N, N, N, N, N, N, N,
        /* 0x20 - 0x2F */
-       D(ModRM | DstMem | Priv | Op3264), D(ModRM | DstMem | Priv | Op3264),
-       D(ModRM | SrcMem | Priv | Op3264), D(ModRM | SrcMem | Priv | Op3264),
+       DIP(ModRM | DstMem | Priv | Op3264, cr_read, check_cr_read),
+       D(ModRM | DstMem | Priv | Op3264),
+       DIP(ModRM | SrcMem | Priv | Op3264, cr_write, check_cr_write),
+       D(ModRM | SrcMem | Priv | Op3264),
        N, N, N, N,
        N, N, N, N, N, N, N, N,
        /* 0x30 - 0x3F */
@@ -3724,14 +3815,6 @@ twobyte_insn:
        case 0x18:              /* Grp16 (prefetch/nop) */
                break;
        case 0x20: /* mov cr, reg */
-               switch (c->modrm_reg) {
-               case 1:
-               case 5 ... 7:
-               case 9 ... 15:
-                       emulate_ud(ctxt);
-                       rc = X86EMUL_PROPAGATE_FAULT;
-                       goto done;
-               }
                c->dst.val = ops->get_cr(c->modrm_reg, ctxt->vcpu);
                break;
        case 0x21: /* mov from dr to reg */
index 798ebe695f1d984f71b3864f97784f2b400ddf94..ff4ed3619d00d90faefbd34bc38d44c0255d0f1b 100644 (file)
@@ -3868,11 +3868,90 @@ static void svm_fpu_deactivate(struct kvm_vcpu *vcpu)
        update_cr0_intercept(svm);
 }
 
+#define POST_EX(exit) { .exit_code = (exit), \
+                       .stage = X86_ICPT_POST_EXCEPT, \
+                       .valid = true }
+
+static struct __x86_intercept {
+       u32 exit_code;
+       enum x86_intercept_stage stage;
+       bool valid;
+} x86_intercept_map[] = {
+       [x86_intercept_cr_read]         = POST_EX(SVM_EXIT_READ_CR0),
+       [x86_intercept_cr_write]        = POST_EX(SVM_EXIT_WRITE_CR0),
+       [x86_intercept_clts]            = POST_EX(SVM_EXIT_WRITE_CR0),
+       [x86_intercept_lmsw]            = POST_EX(SVM_EXIT_WRITE_CR0),
+       [x86_intercept_smsw]            = POST_EX(SVM_EXIT_READ_CR0),
+};
+
+#undef POST_EX
+
 static int svm_check_intercept(struct kvm_vcpu *vcpu,
                               struct x86_instruction_info *info,
                               enum x86_intercept_stage stage)
 {
-       return X86EMUL_CONTINUE;
+       struct vcpu_svm *svm = to_svm(vcpu);
+       int vmexit, ret = X86EMUL_CONTINUE;
+       struct __x86_intercept icpt_info;
+       struct vmcb *vmcb = svm->vmcb;
+
+       if (info->intercept >= ARRAY_SIZE(x86_intercept_map))
+               goto out;
+
+       icpt_info = x86_intercept_map[info->intercept];
+
+       if (!icpt_info.valid || stage != icpt_info.stage)
+               goto out;
+
+       switch (icpt_info.exit_code) {
+       case SVM_EXIT_READ_CR0:
+               if (info->intercept == x86_intercept_cr_read)
+                       icpt_info.exit_code += info->modrm_reg;
+               break;
+       case SVM_EXIT_WRITE_CR0: {
+               unsigned long cr0, val;
+               u64 intercept;
+
+               if (info->intercept == x86_intercept_cr_write)
+                       icpt_info.exit_code += info->modrm_reg;
+
+               if (icpt_info.exit_code != SVM_EXIT_WRITE_CR0)
+                       break;
+
+               intercept = svm->nested.intercept;
+
+               if (!(intercept & (1ULL << INTERCEPT_SELECTIVE_CR0)))
+                       break;
+
+               cr0 = vcpu->arch.cr0 & ~SVM_CR0_SELECTIVE_MASK;
+               val = info->src_val  & ~SVM_CR0_SELECTIVE_MASK;
+
+               if (info->intercept == x86_intercept_lmsw) {
+                       cr0 &= 0xfUL;
+                       val &= 0xfUL;
+                       /* lmsw can't clear PE - catch this here */
+                       if (cr0 & X86_CR0_PE)
+                               val |= X86_CR0_PE;
+               }
+
+               if (cr0 ^ val)
+                       icpt_info.exit_code = SVM_EXIT_CR0_SEL_WRITE;
+
+               break;
+       }
+       default:
+               break;
+       }
+
+       vmcb->control.next_rip  = info->next_rip;
+       vmcb->control.exit_code = icpt_info.exit_code;
+       vmexit = nested_svm_exit_handled(svm);
+
+       ret = (vmexit == NESTED_EXIT_DONE) ? X86EMUL_INTERCEPTED
+                                          : X86EMUL_CONTINUE;
+
+out:
+       return ret;
 }
 
 static struct kvm_x86_ops svm_x86_ops = {
index eebe5465c8ce878f2cf7f5a9b3c7d1ead373e1e6..0d6524fa2affb114b22be4e98b4c36405ed33f0f 100644 (file)
 #include <asm/div64.h>
 
 #define MAX_IO_MSRS 256
-#define CR0_RESERVED_BITS                                              \
-       (~(unsigned long)(X86_CR0_PE | X86_CR0_MP | X86_CR0_EM | X86_CR0_TS \
-                         | X86_CR0_ET | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM \
-                         | X86_CR0_NW | X86_CR0_CD | X86_CR0_PG))
-#define CR4_RESERVED_BITS                                              \
-       (~(unsigned long)(X86_CR4_VME | X86_CR4_PVI | X86_CR4_TSD | X86_CR4_DE\
-                         | X86_CR4_PSE | X86_CR4_PAE | X86_CR4_MCE     \
-                         | X86_CR4_PGE | X86_CR4_PCE | X86_CR4_OSFXSR  \
-                         | X86_CR4_OSXSAVE \
-                         | X86_CR4_OSXMMEXCPT | X86_CR4_VMXE))
-
-#define CR8_RESERVED_BITS (~(unsigned long)X86_CR8_TPR)
-
 #define KVM_MAX_MCE_BANKS 32
 #define KVM_MCE_CAP_SUPPORTED (MCG_CTL_P | MCG_SER_P)