[PATCH v4 05/10] common/domain: allocate vmtrace_pt_buffer

[Michał Leszczyński <michal.leszczynski@xxxxxxx>]

From: Michal Leszczynski <michal.leszczynski@xxxxxxx>

Allocate processor trace buffer for each vCPU when the domain
is created, deallocate trace buffers on domain destruction.

Signed-off-by: Michal Leszczynski <michal.leszczynski@xxxxxxx>
---
 xen/arch/x86/domain.c        | 11 +++++++++++
 xen/common/domain.c          | 32 ++++++++++++++++++++++++++++++++
 xen/include/asm-x86/domain.h |  4 ++++
 xen/include/xen/sched.h      |  4 ++++
 4 files changed, 51 insertions(+)

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index fee6c3931a..0d79fd390c 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -2199,6 +2199,17 @@ int domain_relinquish_resources(struct domain *d)
                 altp2m_vcpu_disable_ve(v);
         }
 
+        for_each_vcpu ( d, v )
+        {
+            if ( !v->arch.vmtrace.pt_buf )
+                continue;
+
+            vmtrace_destroy_pt(v);
+
+            free_domheap_pages(v->arch.vmtrace.pt_buf,
+                get_order_from_bytes(v->domain->vmtrace_pt_size));
+        }
+
         if ( is_pv_domain(d) )
         {
             for_each_vcpu ( d, v )
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 27dcfbac8c..8513659ef8 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -137,6 +137,31 @@ static void vcpu_destroy(struct vcpu *v)
     free_vcpu_struct(v);
 }
 
+static int vmtrace_alloc_buffers(struct vcpu *v)
+{
+    struct page_info *pg;
+    uint64_t size = v->domain->vmtrace_pt_size;
+
+    if ( size < PAGE_SIZE || size > GB(4) || (size & (size - 1)) )
+    {
+        /*
+         * We don't accept trace buffer size smaller than single page
+         * and the upper bound is defined as 4GB in the specification.
+         * The buffer size must be also a power of 2.
+         */
+        return -EINVAL;
+    }
+
+    pg = alloc_domheap_pages(v->domain, get_order_from_bytes(size),
+                             MEMF_no_refcount);
+
+    if ( !pg )
+        return -ENOMEM;
+
+    v->arch.vmtrace.pt_buf = pg;
+    return 0;
+}
+
 struct vcpu *vcpu_create(struct domain *d, unsigned int vcpu_id)
 {
     struct vcpu *v;
@@ -162,6 +187,9 @@ struct vcpu *vcpu_create(struct domain *d, unsigned int 
vcpu_id)
     v->vcpu_id = vcpu_id;
     v->dirty_cpu = VCPU_CPU_CLEAN;
 
+    if ( d->vmtrace_pt_size && vmtrace_alloc_buffers(v) != 0 )
+        return NULL;
+
     spin_lock_init(&v->virq_lock);
 
     tasklet_init(&v->continue_hypercall_tasklet, NULL, NULL);
@@ -188,6 +216,9 @@ struct vcpu *vcpu_create(struct domain *d, unsigned int 
vcpu_id)
     if ( arch_vcpu_create(v) != 0 )
         goto fail_sched;
 
+    if ( d->vmtrace_pt_size && vmtrace_init_pt(v) != 0 )
+        goto fail_sched;
+
     d->vcpu[vcpu_id] = v;
     if ( vcpu_id != 0 )
     {
@@ -422,6 +453,7 @@ 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/domain.h b/xen/include/asm-x86/domain.h
index 6fd94c2e14..b01c107f5c 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -627,6 +627,10 @@ struct arch_vcpu
     struct {
         bool next_interrupt_enabled;
     } monitor;
+
+    struct {
+        struct page_info *pt_buf;
+    } vmtrace;
 };
 
 struct guest_memory_policy
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index ac53519d7f..48f0a61bbd 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -457,6 +457,10 @@ struct domain
     unsigned    pbuf_idx;
     spinlock_t  pbuf_lock;
 
+    /* Used by vmtrace features */
+    spinlock_t  vmtrace_lock;
+    uint64_t    vmtrace_pt_size;
+
     /* OProfile support. */
     struct xenoprof *xenoprof;
 
-- 
2.20.1