From 3718938c1acc165ba98dce4cac1c75f93a740017 Mon Sep 17 00:00:00 2001
From: Karol Herbst <kherbst@redhat.com>
Date: Thu, 20 Aug 2020 17:05:13 +0200
Subject: [PATCH] clover: track allocated svm pointers

We need those to proper validate the SVM API.

v2: use std::map instead of std::unordered_map
v3: guard against segfaults on std::prev with empty containers

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6401>
---
 src/gallium/frontends/clover/api/memory.cpp   |  8 +++++++-
 src/gallium/frontends/clover/api/transfer.cpp |  7 +++++--
 src/gallium/frontends/clover/core/context.cpp | 29 +++++++++++++++++++++++++++
 src/gallium/frontends/clover/core/context.hpp | 12 +++++++++++
 4 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/src/gallium/frontends/clover/api/memory.cpp b/src/gallium/frontends/clover/api/memory.cpp
index 1ffe306..5014e7e 100644
--- a/src/gallium/frontends/clover/api/memory.cpp
+++ b/src/gallium/frontends/clover/api/memory.cpp
@@ -519,6 +519,10 @@ clSVMAlloc(cl_context d_ctx,
       if (alignment < sizeof(void*))
          alignment = sizeof(void*);
       posix_memalign(&ptr, alignment, size);
+
+      if (ptr)
+         ctx.add_svm_allocation(ptr, size);
+
       return ptr;
    }
 #endif
@@ -540,8 +544,10 @@ clSVMFree(cl_context d_ctx,
 
    bool can_emulate = all_of(std::mem_fn(&device::has_system_svm), ctx.devices());
 
-   if (can_emulate)
+   if (can_emulate) {
+      ctx.remove_svm_allocation(svm_pointer);
       return free(svm_pointer);
+   }
 
    CLOVER_NOT_SUPPORTED_UNTIL("2.0");
 
diff --git a/src/gallium/frontends/clover/api/transfer.cpp b/src/gallium/frontends/clover/api/transfer.cpp
index d1da88f..ff20431 100644
--- a/src/gallium/frontends/clover/api/transfer.cpp
+++ b/src/gallium/frontends/clover/api/transfer.cpp
@@ -969,10 +969,13 @@ clover::EnqueueSVMFree(cl_command_queue d_q,
          CLOVER_NOT_SUPPORTED_UNTIL("2.0");
          return CL_INVALID_VALUE;
       }
-      pfn_free_func = [](cl_command_queue, cl_uint num_svm_pointers,
+      pfn_free_func = [](cl_command_queue d_q, cl_uint num_svm_pointers,
                          void *svm_pointers[], void *) {
-         for (void *p : range(svm_pointers, num_svm_pointers))
+         clover::context &ctx = obj(d_q).context();
+         for (void *p : range(svm_pointers, num_svm_pointers)) {
+            ctx.remove_svm_allocation(p);
             free(p);
+         }
       };
    }
 
diff --git a/src/gallium/frontends/clover/core/context.cpp b/src/gallium/frontends/clover/core/context.cpp
index e5255e7..d81fbec 100644
--- a/src/gallium/frontends/clover/core/context.cpp
+++ b/src/gallium/frontends/clover/core/context.cpp
@@ -61,3 +61,32 @@ context::device_range
 context::devices() const {
    return map(evals(), devs);
 }
+
+void
+context::add_svm_allocation(const void *ptr, size_t size) {
+   svm_ptrs.emplace(ptr, size);
+}
+
+void
+context::remove_svm_allocation(const void *ptr) {
+   svm_ptrs.erase(ptr);
+}
+
+context::svm_pointer_map::value_type
+context::find_svm_allocation(const void *ptr) const {
+   // std::prev on an iterator of an empty container causes SIGSEGVs
+   if (svm_ptrs.empty())
+      return { nullptr, 0 };
+
+   auto it = std::prev(svm_ptrs.upper_bound(ptr));
+   if (it == svm_ptrs.end())
+      return { nullptr, 0 };
+
+   uintptr_t base = reinterpret_cast<uintptr_t>((*it).first);
+   uintptr_t end  = (*it).second + base;
+   uintptr_t ptrv = reinterpret_cast<uintptr_t>(ptr);
+   if (ptrv >= base && ptrv < end)
+      return *it;
+
+   return { nullptr, 0 };
+}
diff --git a/src/gallium/frontends/clover/core/context.hpp b/src/gallium/frontends/clover/core/context.hpp
index bbde48b..2ecde23 100644
--- a/src/gallium/frontends/clover/core/context.hpp
+++ b/src/gallium/frontends/clover/core/context.hpp
@@ -23,6 +23,7 @@
 #ifndef CLOVER_CORE_CONTEXT_HPP
 #define CLOVER_CORE_CONTEXT_HPP
 
+#include <map>
 #include <stack>
 
 #include "core/object.hpp"
@@ -41,6 +42,7 @@ namespace clover {
       ~context();
 
       typedef std::function<void (const char *)> notify_action;
+      typedef std::map<const void *, size_t> svm_pointer_map;
 
       context(const property_list &props, const ref_vector<device> &devs,
               const notify_action &notify);
@@ -62,12 +64,22 @@ namespace clover {
       device_range
       devices() const;
 
+      void
+      add_svm_allocation(const void *ptr, size_t size);
+
+      void
+      remove_svm_allocation(const void *ptr);
+
+      svm_pointer_map::value_type
+      find_svm_allocation(const void *ptr) const;
+
       const notify_action notify;
 
    private:
       property_list props;
       const std::vector<intrusive_ref<device>> devs;
       std::stack<std::function<void ()>> _destroy_notify;
+      svm_pointer_map svm_ptrs;
    };
 }
 
-- 
2.7.4