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[v5,3/3] x86/viridian: implement the crash MSRs

Message ID 1490196489-16021-4-git-send-email-paul.durrant@citrix.com (mailing list archive)
State New, archived
Headers show

Commit Message

Paul Durrant March 22, 2017, 3:28 p.m. UTC 
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>
---
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Paul Durrant <paul.durrant@citrix.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>

v5:
 - Fix LIBXL_HAVE_... name

v4:
 - Name the union in HV_CRASH_CTL_REG_CONTENTS to keep older gcc happy

v3:
 - Use WARNING level message rather than INFO

v2:
 - Make MSRs per-vcpu rather than per-domain
 - Fix hypervisor stack leak
 - Replicate BUILD_BOG_ON()
 - Use gprintk() rather than printk()
---
 docs/man/xl.cfg.pod.5.in           | 10 ++++--
 tools/libxl/libxl.h                |  6 ++++
 tools/libxl/libxl_dom.c            |  4 +++
 tools/libxl/libxl_types.idl        |  1 +
 xen/arch/x86/hvm/viridian.c        | 69 ++++++++++++++++++++++++++++++++++++++
 xen/include/asm-x86/hvm/viridian.h |  1 +
 xen/include/public/hvm/params.h    |  7 +++-
 7 files changed, 95 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/docs/man/xl.cfg.pod.5.in b/docs/man/xl.cfg.pod.5.in
index 52802d5..991960b 100644
--- 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 72ec39d..833f866 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -288,6 +288,12 @@ 
 #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
  *
  * The only guarantee which libxl makes regarding ABI compatibility
diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
index c88b904..cf03ded 100644
--- 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 2475a4d..69e789a 100644
--- 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 4c65ddc..986fde5 100644
--- 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 271c36d..30259e9 100644
--- 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 58c8478..19c9eb8 100644
--- 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