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[SYCL][Docs] Clarify virtual memory accessibility #20576

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merged 3 commits into from
Nov 10, 2025
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[SYCL][Docs] Clarify virtual memory accessibility #20576

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[SYCL][Docs] Clarify virtual memory accessibility
steffenlarsen Nov 6, 2025
c73a5f8
Change wording to reference peer access extension
steffenlarsen Nov 10, 2025
819b1b1
Fix links
steffenlarsen Nov 10, 2025
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12 changes: 12 additions & 0 deletions sycl/doc/extensions/experimental/sycl_ext_oneapi_virtual_mem.asciidoc
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Original file line number Diff line number Diff line change
Expand Up @@ -298,6 +298,12 @@ the returned pointer is accessible after the call as read-only or read-write
respectively. Otherwise, it is considered inaccessible and accessing it will
result in undefined behavior.

If other devices in the context associated with this instance of `physical_mem`
have enabled peer-to-peer access with the device associated with this instance
of `physical_mem` via link:../supported/sycl_ext_oneapi_peer_access.asciidoc[
sycl_ext_oneapi_peer_access], those other devices also have access to this
mapped memory, and the access mode applies to accesses from those devices also.

The returned pointer is equivalent to `reinterpret_cast<void *>(ptr)`.

Writing to any address in the virtual memory range with access mode set to
Expand Down Expand Up @@ -353,6 +359,12 @@ If `mode` is `address_access_mode::read` or `address_access_mode::read_write`
respectively. Otherwise, it is considered inaccessible and accessing it will
result in undefined behavior.

If other devices in `syclContext` have enabled peer-to-peer access with the
device on which the memory referenced by `ptr` resides via
link:../supported/sycl_ext_oneapi_peer_access.asciidoc[
sycl_ext_oneapi_peer_access], those other devices also have access to this
mapped memory, and the access mode applies to accesses from those devices also.

The virtual memory range specified by `ptr` and `numBytes` must be a sub-range
of virtual memory ranges previously mapped to `physical_mem`. `ptr`
must be aligned to the minimum memory granularity of the device associated with
Expand Down