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[PATCH v2 4/7] x86/vmx: add do_vmtrace_op



Provide an interface for privileged domains to manage
external IPT monitoring. Guest IPT state will be preserved
across vmentry/vmexit using ipt_state structure.

Signed-off-by: Michal Leszczynski <michal.leszczynski@xxxxxxx>
---
 xen/arch/x86/hvm/hvm.c             | 167 +++++++++++++++++++++++++++++
 xen/arch/x86/hvm/vmx/vmx.c         |  24 +++++
 xen/arch/x86/mm.c                  |  37 +++++++
 xen/common/domain.c                |   1 +
 xen/include/asm-x86/hvm/vmx/vmcs.h |  16 +++
 xen/include/public/hvm/hvm_op.h    |  23 ++++
 xen/include/public/hvm/params.h    |   5 +-
 xen/include/public/memory.h        |   1 +
 xen/include/xen/sched.h            |   3 +
 9 files changed, 276 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 5bb47583b3..145ad053d2 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -1612,6 +1612,24 @@ int hvm_vcpu_initialise(struct vcpu *v)
     return rc;
 }
 
+void hvm_vmtrace_destroy(struct vcpu *v)
+{
+    unsigned int i;
+    struct page_info *pg;
+    struct ipt_state *ipt = v->arch.hvm.vmx.ipt_state;
+    mfn_t buf_mfn = ipt->output_base >> PAGE_SHIFT;
+    size_t buf_size = ipt->output_mask.size + 1;
+
+    xfree(ipt);
+    v->arch.hvm.vmx.ipt_state = NULL;
+
+    for ( i = 0; i < (buf_size >> PAGE_SHIFT); i++ )
+    {
+        pg = mfn_to_page(_mfn(mfn_add(buf_mfn, i)));
+        free_domheap_page(pg);
+    }
+}
+
 void hvm_vcpu_destroy(struct vcpu *v)
 {
     viridian_vcpu_deinit(v);
@@ -1631,6 +1649,8 @@ void hvm_vcpu_destroy(struct vcpu *v)
     vlapic_destroy(v);
 
     hvm_vcpu_cacheattr_destroy(v);
+
+    hvm_vmtrace_destroy(v);
 }
 
 void hvm_vcpu_down(struct vcpu *v)
@@ -4066,6 +4086,51 @@ static int hvmop_set_evtchn_upcall_vector(
     return 0;
 }
 
+static int hvm_set_vmtrace_pt_size(struct domain *d, uint64_t value)
+{
+    void *buf;
+    unsigned int buf_order;
+    struct page_info *pg;
+    struct ipt_state *ipt;
+    struct vcpu *v;
+
+    if ( value < PAGE_SIZE ||
+         value > GB(4) ||
+         ( value & (value - 1) ) ) {
+        /* we don't accept trace buffer size smaller than single page
+         * and the upper bound is defined as 4GB in the specification */
+        return -EINVAL;
+    }
+
+    for_each_vcpu ( d, v )
+    {
+        buf_order = get_order_from_bytes(value);
+        pg = alloc_domheap_pages(d, buf_order, MEMF_no_refcount);
+
+        if ( !pg )
+            return -EFAULT;
+
+        buf = page_to_virt(pg);
+
+        if ( vmx_add_host_load_msr(v, MSR_RTIT_CTL, 0) )
+            return -EFAULT;
+
+        ipt = xmalloc(struct ipt_state);
+
+        if ( !ipt )
+            return -EFAULT;
+
+        ipt->output_base = virt_to_mfn(buf) << PAGE_SHIFT;
+        ipt->output_mask.raw = value - 1;
+        ipt->status = 0;
+        ipt->active = 0;
+
+        v->arch.hvm.vmx.ipt_state = ipt;
+    }
+
+    return 0;
+}
+
 static int hvm_allow_set_param(struct domain *d,
                                uint32_t index,
                                uint64_t new_value)
@@ -4127,6 +4192,7 @@ static int hvm_allow_set_param(struct domain *d,
     case HVM_PARAM_NR_IOREQ_SERVER_PAGES:
     case HVM_PARAM_ALTP2M:
     case HVM_PARAM_MCA_CAP:
+    case HVM_PARAM_VMTRACE_PT_SIZE:
         if ( value != 0 && new_value != value )
             rc = -EEXIST;
         break;
@@ -4328,6 +4394,9 @@ static int hvm_set_param(struct domain *d, uint32_t 
index, uint64_t value)
     case HVM_PARAM_MCA_CAP:
         rc = vmce_enable_mca_cap(d, value);
         break;
+    case HVM_PARAM_VMTRACE_PT_SIZE:
+        rc = hvm_set_vmtrace_pt_size(d, value);
+        break;
     }
 
     if ( !rc )
@@ -4949,6 +5018,100 @@ static int compat_altp2m_op(
     return rc;
 }
 
+static int do_vmtrace_op(XEN_GUEST_HANDLE_PARAM(void) arg)
+{
+    struct xen_hvm_vmtrace_op a;
+    struct domain *d;
+    int rc;
+    struct vcpu *v;
+    struct ipt_state *ipt;
+
+    if ( !hvm_pt_supported() )
+        return -EOPNOTSUPP;
+
+    if ( copy_from_guest(&a, arg, 1) )
+        return -EFAULT;
+
+    if ( a.version != HVMOP_VMTRACE_INTERFACE_VERSION )
+        return -EINVAL;
+
+    d = rcu_lock_domain_by_any_id(a.domain);
+    spin_lock(&d->vmtrace_lock);
+
+    if ( d == NULL )
+        return -ESRCH;
+
+    if ( !is_hvm_domain(d) )
+    {
+        rc = -EOPNOTSUPP;
+        goto out;
+    }
+
+    domain_pause(d);
+
+    if ( a.vcpu >= d->max_vcpus )
+    {
+        rc = -EINVAL;
+        goto out;
+    }
+
+    v = d->vcpu[a.vcpu];
+    ipt = v->arch.hvm.vmx.ipt_state;
+
+    if ( !ipt )
+    {
+        /*
+        * PT must be first initialized upon domain creation.
+        */
+        rc = -EINVAL;
+        goto out;
+    }
+
+    switch ( a.cmd )
+    {
+    case HVMOP_vmtrace_ipt_enable:
+        if ( vmx_add_guest_msr(v, MSR_RTIT_CTL,
+                               RTIT_CTL_TRACEEN | RTIT_CTL_OS |
+                               RTIT_CTL_USR | RTIT_CTL_BRANCH_EN) )
+        {
+            rc = -EFAULT;
+            goto out;
+        }
+
+        ipt->active = 1;
+        break;
+    case HVMOP_vmtrace_ipt_disable:
+        if ( vmx_add_guest_msr(v, MSR_RTIT_CTL, 0) )
+        {
+            rc = -EFAULT;
+            goto out;
+        }
+
+        ipt->active = 0;
+        break;
+    case HVMOP_vmtrace_ipt_get_offset:
+        a.offset = ipt->output_mask.offset;
+        break;
+    default:
+        rc = -EOPNOTSUPP;
+        goto out;
+    }
+
+    rc = -EFAULT;
+    if ( __copy_to_guest(arg, &a, 1) )
+      goto out;
+    rc = 0;
+
+ out:
+    domain_unpause(d);
+    spin_unlock(&d->vmtrace_lock);
+    rcu_unlock_domain(d);
+
+    return rc;
+}
+
+DEFINE_XEN_GUEST_HANDLE(compat_hvm_vmtrace_op_t);
+
 static int hvmop_get_mem_type(
     XEN_GUEST_HANDLE_PARAM(xen_hvm_get_mem_type_t) arg)
 {
@@ -5101,6 +5264,10 @@ long do_hvm_op(unsigned long op, 
XEN_GUEST_HANDLE_PARAM(void) arg)
         rc = current->hcall_compat ? compat_altp2m_op(arg) : do_altp2m_op(arg);
         break;
 
+    case HVMOP_vmtrace:
+        rc = do_vmtrace_op(arg);
+        break;
+
     default:
     {
         gdprintk(XENLOG_DEBUG, "Bad HVM op %ld.\n", op);
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index ab19d9424e..51f0046483 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -508,11 +508,25 @@ static void vmx_restore_host_msrs(void)
 
 static void vmx_save_guest_msrs(struct vcpu *v)
 {
+    uint64_t rtit_ctl;
+
     /*
      * We cannot cache SHADOW_GS_BASE while the VCPU runs, as it can
      * be updated at any time via SWAPGS, which we cannot trap.
      */
     v->arch.hvm.vmx.shadow_gs = rdgsshadow();
+
+    if ( unlikely(v->arch.hvm.vmx.ipt_state && 
v->arch.hvm.vmx.ipt_state->active) )
+    {
+        smp_rmb();
+        rdmsrl(MSR_RTIT_CTL, rtit_ctl);
+
+        if ( rtit_ctl & RTIT_CTL_TRACEEN )
+            BUG();
+
+        rdmsrl(MSR_RTIT_STATUS, v->arch.hvm.vmx.ipt_state->status);
+        rdmsrl(MSR_RTIT_OUTPUT_MASK, 
v->arch.hvm.vmx.ipt_state->output_mask.raw);
+    }
 }
 
 static void vmx_restore_guest_msrs(struct vcpu *v)
@@ -524,6 +538,16 @@ static void vmx_restore_guest_msrs(struct vcpu *v)
 
     if ( cpu_has_msr_tsc_aux )
         wrmsr_tsc_aux(v->arch.msrs->tsc_aux);
+
+    if ( unlikely(v->arch.hvm.vmx.ipt_state && 
v->arch.hvm.vmx.ipt_state->active) )
+    {
+        wrmsrl(MSR_RTIT_OUTPUT_BASE,
+            v->arch.hvm.vmx.ipt_state->output_base);
+        wrmsrl(MSR_RTIT_OUTPUT_MASK,
+            v->arch.hvm.vmx.ipt_state->output_mask.raw);
+        wrmsrl(MSR_RTIT_STATUS,
+            v->arch.hvm.vmx.ipt_state->status);
+    }
 }
 
 void vmx_update_cpu_exec_control(struct vcpu *v)
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index e376fc7e8f..e4658dc27f 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -4624,6 +4624,43 @@ int arch_acquire_resource(struct domain *d, unsigned int 
type,
         }
         break;
     }
+
+    case XENMEM_resource_vmtrace_buf:
+    {
+        mfn_t mfn;
+        unsigned int i;
+        struct ipt_state *ipt;
+
+        if ( id >= d->max_vcpus )
+        {
+            rc = -EINVAL;
+            break;
+        }
+
+        ipt = d->vcpu[id]->arch.hvm.vmx.ipt_state;
+
+        if ( !ipt )
+        {
+            rc = -EINVAL;
+            break;
+        }
+
+        mfn = mfn_x(ipt->output_base >> PAGE_SHIFT);
+
+        if (nr_frames > ( ( ipt->output_mask.size + 1 ) >> PAGE_SHIFT ))
+        {
+            rc = -EINVAL;
+            break;
+        }
+
+        rc = 0;
+        for ( i = 0; i < nr_frames; i++ )
+        {
+            mfn_list[i] = mfn_add(mfn, i);
+        }
+
+        break;
+    }
 #endif
 
     default:
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 7cc9526139..6f6458cd5b 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -414,6 +414,7 @@ struct domain *domain_create(domid_t domid,
     d->shutdown_code = SHUTDOWN_CODE_INVALID;
 
     spin_lock_init(&d->pbuf_lock);
+    spin_lock_init(&d->vmtrace_lock);
 
     rwlock_init(&d->vnuma_rwlock);
 
diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h 
b/xen/include/asm-x86/hvm/vmx/vmcs.h
index 4c81093aba..9fc4653777 100644
--- a/xen/include/asm-x86/hvm/vmx/vmcs.h
+++ b/xen/include/asm-x86/hvm/vmx/vmcs.h
@@ -104,6 +104,19 @@ struct pi_blocking_vcpu {
     spinlock_t           *lock;
 };
 
+struct ipt_state {
+    uint64_t active;
+    uint64_t status;
+    uint64_t output_base;
+    union {
+        uint64_t raw;
+        struct {
+            uint32_t size;
+            uint32_t offset;
+        };
+    } output_mask;
+};
+
 struct vmx_vcpu {
     /* Physical address of VMCS. */
     paddr_t              vmcs_pa;
@@ -186,6 +199,9 @@ struct vmx_vcpu {
      * pCPU and wakeup the related vCPU.
      */
     struct pi_blocking_vcpu pi_blocking;
+
+    /* State of Intel Processor Trace feature */
+    struct ipt_state     *ipt_state;
 };
 
 int vmx_create_vmcs(struct vcpu *v);
diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
index 870ec52060..8cd0b6ea49 100644
--- a/xen/include/public/hvm/hvm_op.h
+++ b/xen/include/public/hvm/hvm_op.h
@@ -382,6 +382,29 @@ struct xen_hvm_altp2m_op {
 typedef struct xen_hvm_altp2m_op xen_hvm_altp2m_op_t;
 DEFINE_XEN_GUEST_HANDLE(xen_hvm_altp2m_op_t);
 
+/* HVMOP_vmtrace: Perform VM tracing related operation */
+#define HVMOP_vmtrace 26
+
+#define HVMOP_VMTRACE_INTERFACE_VERSION 0x00000001
+
+struct xen_hvm_vmtrace_op {
+    /* IN variable */
+    uint32_t version;   /* HVMOP_VMTRACE_INTERFACE_VERSION */
+    uint32_t cmd;
+/* Enable/disable external vmtrace for given domain */
+#define HVMOP_vmtrace_ipt_enable      1
+#define HVMOP_vmtrace_ipt_disable     2
+#define HVMOP_vmtrace_ipt_get_offset  3
+    domid_t domain;
+    uint32_t vcpu;
+    uint64_t size;
+
+    /* OUT variable */
+    uint64_t offset;
+};
+typedef struct xen_hvm_vmtrace_op xen_hvm_vmtrace_op_t;
+DEFINE_XEN_GUEST_HANDLE(xen_hvm_vmtrace_op_t);
+
 #endif /* __XEN_PUBLIC_HVM_HVM_OP_H__ */
 
 /*
diff --git a/xen/include/public/hvm/params.h b/xen/include/public/hvm/params.h
index 0a91bfa749..adbc7e5d08 100644
--- a/xen/include/public/hvm/params.h
+++ b/xen/include/public/hvm/params.h
@@ -300,6 +300,9 @@
 #define XEN_HVM_MCA_CAP_LMCE   (xen_mk_ullong(1) << 0)
 #define XEN_HVM_MCA_CAP_MASK   XEN_HVM_MCA_CAP_LMCE
 
-#define HVM_NR_PARAMS 39
+/* VM trace capabilities */
+#define HVM_PARAM_VMTRACE_PT_SIZE 39
+
+#define HVM_NR_PARAMS 40
 
 #endif /* __XEN_PUBLIC_HVM_PARAMS_H__ */
diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
index dbd35305df..f823c784c3 100644
--- a/xen/include/public/memory.h
+++ b/xen/include/public/memory.h
@@ -620,6 +620,7 @@ struct xen_mem_acquire_resource {
 
 #define XENMEM_resource_ioreq_server 0
 #define XENMEM_resource_grant_table 1
+#define XENMEM_resource_vmtrace_buf 2
 
     /*
      * IN - a type-specific resource identifier, which must be zero
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index ac53519d7f..b3a36f3788 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -457,6 +457,9 @@ struct domain
     unsigned    pbuf_idx;
     spinlock_t  pbuf_lock;
 
+    /* Used by vmtrace domctls */
+    spinlock_t  vmtrace_lock;
+
     /* OProfile support. */
     struct xenoprof *xenoprof;
 
-- 
2.20.1




 


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