[Xen-devel] [PATCH v3] SVM: clean up svm_vmcb_isvalid()

["Jan Beulich" <JBeulich@xxxxxxxx>]

- correct CR3, CR4, and EFER checks
- delete bogus nested paging check
- add vcpu parameter (to include in log messages) and constify vmcb one
- use bool/true/false
- use accessors (and local variables to improve code readability)
- adjust formatting

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
v3: Use local variables.
v2: Constrain CR3 checks to the case when CR0.PG is set. Change wording
    of CR4 related message and also log valid bit mask there. Tighten
    EFER checks. Delete bogus nested paging check. Correct indentation
    in a few places.

--- a/xen/arch/x86/hvm/svm/nestedsvm.c
+++ b/xen/arch/x86/hvm/svm/nestedsvm.c
@@ -658,13 +658,13 @@ static int nsvm_vmcb_prepare4vmrun(struc
     /* Cleanbits */
     n2vmcb->cleanbits.bytes = 0;
 
-    rc = svm_vmcb_isvalid(__func__, ns_vmcb, 1);
+    rc = svm_vmcb_isvalid(__func__, ns_vmcb, v, true);
     if (rc) {
         gdprintk(XENLOG_ERR, "virtual vmcb invalid\n");
         return NSVM_ERROR_VVMCB;
     }
 
-    rc = svm_vmcb_isvalid(__func__, n2vmcb, 1);
+    rc = svm_vmcb_isvalid(__func__, n2vmcb, v, true);
     if (rc) {
         gdprintk(XENLOG_ERR, "n2vmcb invalid\n");
         return NSVM_ERROR_VMENTRY;
--- a/xen/arch/x86/hvm/svm/svmdebug.c
+++ b/xen/arch/x86/hvm/svm/svmdebug.c
@@ -16,6 +16,7 @@
  *
  */
 
+#include <xen/sched.h>
 #include <asm/processor.h>
 #include <asm/msr-index.h>
 #include <asm/hvm/svm/svmdebug.h>
@@ -87,93 +88,75 @@ void svm_vmcb_dump(const char *from, con
     svm_dump_sel("  TR", &vmcb->tr);
 }
 
-bool_t
-svm_vmcb_isvalid(const char *from, struct vmcb_struct *vmcb,
-                 bool_t verbose)
+bool svm_vmcb_isvalid(const char *from, const struct vmcb_struct *vmcb,
+                      const struct vcpu *v, bool verbose)
 {
-    bool_t ret = 0; /* ok */
+    bool ret = false; /* ok */
+    unsigned long cr0 = vmcb_get_cr0(vmcb);
+    unsigned long cr3 = vmcb_get_cr3(vmcb);
+    unsigned long cr4 = vmcb_get_cr4(vmcb);
+    uint64_t efer = vmcb_get_efer(vmcb);
+
+#define PRINTF(fmt, args...) do { \
+    if ( !verbose ) return true; \
+    ret = true; \
+    printk(XENLOG_GUEST "%pv[%s]: " fmt, v, from, ## args); \
+} while (0)
+
+    if ( !(efer & EFER_SVME) )
+        PRINTF("EFER: SVME bit not set (%#"PRIx64")\n", efer);
+
+    if ( !(cr0 & X86_CR0_CD) && (cr0 & X86_CR0_NW) )
+        PRINTF("CR0: CD bit is zero and NW bit set (%#"PRIx64")\n", cr0);
+
+    if ( cr0 >> 32 )
+        PRINTF("CR0: bits [63:32] are not zero (%#"PRIx64")\n", cr0);
+
+    if ( (cr0 & X86_CR0_PG) &&
+         ((cr3 & 7) ||
+          ((!(cr4 & X86_CR4_PAE) || (efer & EFER_LMA)) && (cr3 & 0xfe0)) ||
+          ((efer & EFER_LMA) &&
+           (cr3 >> v->domain->arch.cpuid->extd.maxphysaddr))) )
+        PRINTF("CR3: MBZ bits are set (%#"PRIx64")\n", cr3);
+
+    if ( cr4 & ~hvm_cr4_guest_valid_bits(v, false) )
+        PRINTF("CR4: invalid bits are set (%#"PRIx64", valid: %#"PRIx64")\n",
+               cr4, hvm_cr4_guest_valid_bits(v, false));
 
-#define PRINTF(...) \
-    if (verbose) { ret = 1; printk("%s: ", from); printk(__VA_ARGS__); \
-    } else return 1;
-
-    if ((vmcb->_efer & EFER_SVME) == 0) {
-        PRINTF("EFER: SVME bit not set (%#"PRIx64")\n", vmcb->_efer);
-    }
-
-    if ((vmcb->_cr0 & X86_CR0_CD) == 0 && (vmcb->_cr0 & X86_CR0_NW) != 0) {
-        PRINTF("CR0: CD bit is zero and NW bit set (%#"PRIx64")\n",
-                vmcb->_cr0);
-    }
-
-    if ((vmcb->_cr0 >> 32U) != 0) {
-        PRINTF("CR0: bits [63:32] are not zero (%#"PRIx64")\n",
-                vmcb->_cr0);
-    }
-
-    if ((vmcb->_cr3 & 0x7) != 0) {
-        PRINTF("CR3: MBZ bits are set (%#"PRIx64")\n", vmcb->_cr3);
-    }
-    if ((vmcb->_efer & EFER_LMA) && (vmcb->_cr3 & 0xfe) != 0) {
-        PRINTF("CR3: MBZ bits are set (%#"PRIx64")\n", vmcb->_cr3);
-    }
-
-    if ((vmcb->_cr4 >> 19U) != 0) {
-        PRINTF("CR4: bits [63:19] are not zero (%#"PRIx64")\n",
-                vmcb->_cr4);
-    }
-
-    if (((vmcb->_cr4 >> 11U) & 0x7fU) != 0) {
-        PRINTF("CR4: bits [17:11] are not zero (%#"PRIx64")\n",
-                vmcb->_cr4);
-    }
-
-    if ((vmcb->_dr6 >> 32U) != 0) {
+    if ( vmcb_get_dr6(vmcb) >> 32 )
         PRINTF("DR6: bits [63:32] are not zero (%#"PRIx64")\n",
-                vmcb->_dr6);
-    }
+               vmcb_get_dr6(vmcb));
 
-    if ((vmcb->_dr7 >> 32U) != 0) {
+    if ( vmcb_get_dr7(vmcb) >> 32 )
         PRINTF("DR7: bits [63:32] are not zero (%#"PRIx64")\n",
-                vmcb->_dr7);
-    }
+               vmcb_get_dr7(vmcb));
 
-    if ((vmcb->_efer >> 15U) != 0) {
-        PRINTF("EFER: bits [63:15] are not zero (%#"PRIx64")\n",
-                vmcb->_efer);
-    }
+    if ( efer & ~(EFER_SCE | EFER_LME | EFER_LMA | EFER_NX | EFER_SVME |
+                  EFER_LMSLE | EFER_FFXSE) )
+        PRINTF("EFER: undefined bits are not zero (%#"PRIx64")\n", efer);
 
-    if ((vmcb->_efer & EFER_LME) != 0 && ((vmcb->_cr0 & X86_CR0_PG) != 0)) {
-        if ((vmcb->_cr4 & X86_CR4_PAE) == 0) {
-            PRINTF("EFER_LME and CR0.PG are both set and CR4.PAE is zero.\n");
-        }
-        if ((vmcb->_cr0 & X86_CR0_PE) == 0) {
-            PRINTF("EFER_LME and CR0.PG are both set and CR0.PE is zero.\n");
-        }
-    }
+    if ( hvm_efer_valid(v, efer, -1) )
+        PRINTF("EFER: %s (%"PRIx64")\n", hvm_efer_valid(v, efer, -1), efer);
 
-    if ((vmcb->_efer & EFER_LME) != 0
-        && (vmcb->_cr0 & X86_CR0_PG) != 0
-        && (vmcb->_cr4 & X86_CR4_PAE) != 0
-        && (vmcb->cs.attr.fields.l != 0)
-        && (vmcb->cs.attr.fields.db != 0))
+    if ( (efer & EFER_LME) && (cr0 & X86_CR0_PG) )
     {
-        PRINTF("EFER_LME, CR0.PG, CR4.PAE, CS.L and CS.D are all non-zero.\n");
+        if ( !(cr4 & X86_CR4_PAE) )
+            PRINTF("EFER_LME and CR0.PG are both set and CR4.PAE is zero\n");
+        if ( !(cr0 & X86_CR0_PE) )
+            PRINTF("EFER_LME and CR0.PG are both set and CR0.PE is zero\n");
     }
 
-    if ((vmcb->_general2_intercepts & GENERAL2_INTERCEPT_VMRUN) == 0) {
+    if ( (efer & EFER_LME) && (cr0 & X86_CR0_PG) && (cr4 & X86_CR4_PAE) &&
+         vmcb->cs.attr.fields.l && vmcb->cs.attr.fields.db )
+        PRINTF("EFER_LME, CR0.PG, CR4.PAE, CS.L and CS.D are all non-zero\n");
+
+    if ( !(vmcb_get_general2_intercepts(vmcb) & GENERAL2_INTERCEPT_VMRUN) )
         PRINTF("GENERAL2_INTERCEPT: VMRUN intercept bit is clear 
(%#"PRIx32")\n",
-            vmcb->_general2_intercepts);
-    }
+               vmcb_get_general2_intercepts(vmcb));
 
-    if (vmcb->eventinj.fields.resvd1 != 0) {
+    if ( vmcb->eventinj.fields.resvd1 )
         PRINTF("eventinj: MBZ bits are set (%#"PRIx64")\n",
-                vmcb->eventinj.bytes);
-    }
-
-    if (vmcb->_np_enable && vmcb->_h_cr3 == 0) {
-        PRINTF("nested paging enabled but host cr3 is 0\n");
-    }
+               vmcb->eventinj.bytes);
 
 #undef PRINTF
     return ret;
--- a/xen/include/asm-x86/hvm/svm/svmdebug.h
+++ b/xen/include/asm-x86/hvm/svm/svmdebug.h
@@ -23,7 +23,7 @@
 #include <asm/hvm/svm/vmcb.h>
 
 void svm_vmcb_dump(const char *from, const struct vmcb_struct *vmcb);
-bool_t svm_vmcb_isvalid(const char *from, struct vmcb_struct *vmcb,
-                        bool_t verbose);
+bool svm_vmcb_isvalid(const char *from, const struct vmcb_struct *vmcb,
+                      const struct vcpu *v, bool verbose);
 
 #endif /* __ASM_X86_HVM_SVM_SVMDEBUG_H__ */

Attachment: SVM-isvalid-cleanup.patch
Description: Text document

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