x86/viridian: implement the crash MSRs

Section 2.4.4 of the Hypervisor Top Level Functional Specification states
that enabling bit 10 in EDX of CPUID leaf 3 advertises to Windows a set
of MSRs into which it can write crash information.

This patch advertises that bit and implements the MSRs such that Xen can
log the information if a Windows guest crashes.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>

diff --git a/docs/man/xl.cfg.pod.5.in b/docs/man/xl.cfg.pod.5.in
index 52802d5d60c42f4d475fd70cf2a05e5e74d1c4c4..991960b64becbc40ddd6a7a3df7ba3c296ec34f0 100644 (file)
--- a/docs/man/xl.cfg.pod.5.in
+++ b/docs/man/xl.cfg.pod.5.in
@@ -1601,11 +1601,17 @@ per-vcpu event channel upcall vectors.
 Note that this enlightenment will have no effect if the guest is
 using APICv posted interrupts.
 
+=item B<crash_ctl>
+
+This group incorporates the crash control MSRs. These enlightenments
+allow Windows to write crash information such that it can be logged
+by Xen.
+
 =item B<defaults>
 
 This is a special value that enables the default set of groups, which
-is currently the B<base>, B<freq>, B<time_ref_count> and B<apic_assist>
-groups.
+is currently the B<base>, B<freq>, B<time_ref_count>, B<apic_assist>
+and B<crash_ctl> groups.
 
 =item B<all>
 

diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 72ec39dccb37c26636801e7d92052ca4c8e1f8c7..833f866e49bf74292df06fa07479f47be95677bb 100644 (file)
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -287,6 +287,12 @@
  */
 #define LIBXL_HAVE_SCHED_CREDIT2_PARAMS 1
 
+/*
+ * LIBXL_HAVE_VIRIDIAN_CRASH_CTL indicates that the 'crash_ctl' value
+ * is present in the viridian enlightenment enumeration.
+ */
+#define LIBXL_HAVE_VIRIDIAN_CRASH_CTL 1
+
 /*
  * libxl ABI compatibility
  *

diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index c88b9041d4631f5fe3c6580a81955eb59f7f6a41..cf03ded67d53de5971d2a9e0dd1121b803e2aec7 100644 (file)
--- a/tools/libxl/libxl_dom.c
+++ b/tools/libxl/libxl_dom.c
@@ -214,6 +214,7 @@ static int hvm_set_viridian_features(libxl__gc *gc, uint32_t domid,
         libxl_bitmap_set(&enlightenments, LIBXL_VIRIDIAN_ENLIGHTENMENT_FREQ);
         libxl_bitmap_set(&enlightenments, LIBXL_VIRIDIAN_ENLIGHTENMENT_TIME_REF_COUNT);
         libxl_bitmap_set(&enlightenments, LIBXL_VIRIDIAN_ENLIGHTENMENT_APIC_ASSIST);
+        libxl_bitmap_set(&enlightenments, LIBXL_VIRIDIAN_ENLIGHTENMENT_CRASH_CTL);
     }
 
     libxl_for_each_set_bit(v, info->u.hvm.viridian_enable) {
@@ -259,6 +260,9 @@ static int hvm_set_viridian_features(libxl__gc *gc, uint32_t domid,
     if (libxl_bitmap_test(&enlightenments, LIBXL_VIRIDIAN_ENLIGHTENMENT_APIC_ASSIST))
         mask |= HVMPV_apic_assist;
 
+    if (libxl_bitmap_test(&enlightenments, LIBXL_VIRIDIAN_ENLIGHTENMENT_CRASH_CTL))
+        mask |= HVMPV_crash_ctl;
+
     if (mask != 0 &&
         xc_hvm_param_set(CTX->xch,
                          domid,

diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
index 2475a4df8dfb49c657de7140a23408260c7714be..69e789a0ce5dd6327f2ee55f456db54135496ba0 100644 (file)
--- a/tools/libxl/libxl_types.idl
+++ b/tools/libxl/libxl_types.idl
@@ -224,6 +224,7 @@ libxl_viridian_enlightenment = Enumeration("viridian_enlightenment", [
     (3, "reference_tsc"),
     (4, "hcall_remote_tlb_flush"),
     (5, "apic_assist"),
+    (6, "crash_ctl"),
     ])
 
 libxl_hdtype = Enumeration("hdtype", [

diff --git a/xen/arch/x86/hvm/viridian.c b/xen/arch/x86/hvm/viridian.c
index 4c65ddca54255d7fb80ab239efa5fd63550f3aaf..986fde5832144defeff32a02f9b8a98890d16b57 100644 (file)
--- a/xen/arch/x86/hvm/viridian.c
+++ b/xen/arch/x86/hvm/viridian.c
@@ -154,6 +154,19 @@ typedef struct {
     uint64_t Reserved8:10;
 } HV_PARTITION_PRIVILEGE_MASK;
 
+typedef union _HV_CRASH_CTL_REG_CONTENTS
+{
+    uint64_t AsUINT64;
+    struct
+    {
+        uint64_t Reserved:63;
+        uint64_t CrashNotify:1;
+    } u;
+} HV_CRASH_CTL_REG_CONTENTS;
+
+/* Viridian CPUID leaf 3, Hypervisor Feature Indication */
+#define CPUID3D_CRASH_MSRS (1 << 10)
+
 /* Viridian CPUID leaf 4: Implementation Recommendations. */
 #define CPUID4A_HCALL_REMOTE_TLB_FLUSH (1 << 2)
 #define CPUID4A_MSR_BASED_APIC         (1 << 3)
@@ -246,6 +259,10 @@ void cpuid_viridian_leaves(const struct vcpu *v, uint32_t leaf,
 
         res->a = u.lo;
         res->b = u.hi;
+
+        if ( viridian_feature_mask(d) & HVMPV_crash_ctl )
+            res->d = CPUID3D_CRASH_MSRS;
+
         break;
     }
 
@@ -609,6 +626,36 @@ int wrmsr_viridian_regs(uint32_t idx, uint64_t val)
             update_reference_tsc(d, 1);
         break;
 
+    case HV_X64_MSR_CRASH_P0:
+    case HV_X64_MSR_CRASH_P1:
+    case HV_X64_MSR_CRASH_P2:
+    case HV_X64_MSR_CRASH_P3:
+    case HV_X64_MSR_CRASH_P4:
+        BUILD_BUG_ON(HV_X64_MSR_CRASH_P4 - HV_X64_MSR_CRASH_P0 >=
+                     ARRAY_SIZE(v->arch.hvm_vcpu.viridian.crash_param));
+
+        idx -= HV_X64_MSR_CRASH_P0;
+        v->arch.hvm_vcpu.viridian.crash_param[idx] = val;
+        break;
+
+    case HV_X64_MSR_CRASH_CTL:
+    {
+        HV_CRASH_CTL_REG_CONTENTS ctl;
+
+        ctl.AsUINT64 = val;
+
+        if ( !ctl.u.CrashNotify )
+            break;
+
+        gprintk(XENLOG_WARNING, "VIRIDIAN CRASH: %lx %lx %lx %lx %lx\n",
+                v->arch.hvm_vcpu.viridian.crash_param[0],
+                v->arch.hvm_vcpu.viridian.crash_param[1],
+                v->arch.hvm_vcpu.viridian.crash_param[2],
+                v->arch.hvm_vcpu.viridian.crash_param[3],
+                v->arch.hvm_vcpu.viridian.crash_param[4]);
+        break;
+    }
+
     default:
         if ( idx >= VIRIDIAN_MSR_MIN && idx <= VIRIDIAN_MSR_MAX )
             gprintk(XENLOG_WARNING, "write to unimplemented MSR %#x\n",
@@ -736,6 +783,28 @@ int rdmsr_viridian_regs(uint32_t idx, uint64_t *val)
         break;
     }
 
+    case HV_X64_MSR_CRASH_P0:
+    case HV_X64_MSR_CRASH_P1:
+    case HV_X64_MSR_CRASH_P2:
+    case HV_X64_MSR_CRASH_P3:
+    case HV_X64_MSR_CRASH_P4:
+        BUILD_BUG_ON(HV_X64_MSR_CRASH_P4 - HV_X64_MSR_CRASH_P0 >=
+                     ARRAY_SIZE(v->arch.hvm_vcpu.viridian.crash_param));
+
+        idx -= HV_X64_MSR_CRASH_P0;
+        *val = v->arch.hvm_vcpu.viridian.crash_param[idx];
+        break;
+
+    case HV_X64_MSR_CRASH_CTL:
+    {
+        HV_CRASH_CTL_REG_CONTENTS ctl = {
+            .u.CrashNotify = 1,
+        };
+
+        *val = ctl.AsUINT64;
+        break;
+    }
+
     default:
         if ( idx >= VIRIDIAN_MSR_MIN && idx <= VIRIDIAN_MSR_MAX )
             gprintk(XENLOG_WARNING, "read from unimplemented MSR %#x\n",

diff --git a/xen/include/asm-x86/hvm/viridian.h b/xen/include/asm-x86/hvm/viridian.h
index 271c36da99108ddbabed0c5f24633830ea15d2d1..30259e91b0a07594d89918c9fbb4a1f7fef458d7 100644 (file)
--- a/xen/include/asm-x86/hvm/viridian.h
+++ b/xen/include/asm-x86/hvm/viridian.h
@@ -26,6 +26,7 @@ struct viridian_vcpu
         void *va;
         int vector;
     } vp_assist;
+    uint64_t crash_param[5];
 };
 
 union viridian_guest_os_id

diff --git a/xen/include/public/hvm/params.h b/xen/include/public/hvm/params.h
index 58c8478ad53fe04cfca8df23944f40860e2c6189..19c9eb8886d9cd5a7e3ff0812bcb62113968db41 100644 (file)
--- a/xen/include/public/hvm/params.h
+++ b/xen/include/public/hvm/params.h
@@ -135,13 +135,18 @@
 #define _HVMPV_apic_assist 5
 #define HVMPV_apic_assist (1 << _HVMPV_apic_assist)
 
+/* Enable crash MSRs */
+#define _HVMPV_crash_ctl 6
+#define HVMPV_crash_ctl (1 << _HVMPV_crash_ctl)
+
 #define HVMPV_feature_mask \
         (HVMPV_base_freq | \
          HVMPV_no_freq | \
          HVMPV_time_ref_count | \
          HVMPV_reference_tsc | \
          HVMPV_hcall_remote_tlb_flush | \
-         HVMPV_apic_assist)
+         HVMPV_apic_assist | \
+         HVMPV_crash_ctl)
 
 #endif