<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> </head> <body> <div class="moz-cite-prefix">On 30/06/2022 20:12, Zanoni, Paulo R wrote: </div> <blockquote type="cite" cite="mid:d5fee715c3489b943f055f925935871fda3899e7.camel@intel.com"> <blockquote type="cite" style="color: #007cff;"> <blockquote type="cite" style="color: #007cff;"> <blockquote type="cite" style="color: #007cff;"> <pre class="moz-quote-pre" wrap="">Can you please explain what happens when we try to write to a range that's bound as read-only? </pre> </blockquote> <pre class="moz-quote-pre" wrap="">It will be mapped as read-only in device page table. Hence any write access will fail. I would expect a CAT error reported. </pre> </blockquote> <pre class="moz-quote-pre" wrap="">What's a CAT error? Does this lead to machine freeze or a GPU hang? Let's make sure we document this. </pre> </blockquote> <pre class="moz-quote-pre" wrap="">Catastrophic error. </pre> </blockquote> Reading the documentation, it seems the behavior depends on the context type. With the Legacy 64bit context type, writes are ignored (BSpec 531) : - "<span style="color: rgb(64, 64, 64); font-family: "Segoe UI", "Arial Unicode MS", "Lucida Grande", Helvetica, "Ubuntu Light", "DejaVu Sans", FreeSans, sans-serif; font-size: 14.6667px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); text-decoration-thickness: initial; text-decoration-style: initial; text-decoration-color: initial; display: inline !important; float: none;">For legacy context, the access rights are not applicable and should not be considered during page walk." For Advanced 64bit context type, I think the HW will generate a pagefault. -Lionel </body> </html>