Re: [PATCH] x86/CPU/AMD: avoid printing reset reasons on Xen domU

On Fri, Dec 19, 2025 at 09:36:45AM -0800, Sean Christopherson wrote:

@@ -301,6 +303,20 @@ __ioremap_caller(resource_size_t phys_addr, unsigned long size, if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) goto err_free_area;

•   /*
  

•    * Verify the range was actually mapped when running as a Xen PV DomU
  

•    * guest.  Xen PV doesn't emulate a virtual chipset/motherboard, and
  

•    * disallows DomU from mapping host physical addresses that the domain
  

•    * doesn't own.  Unfortunately, the PTE APIs assume success, and so
  

•    * Xen's rejection of the mapping is ignored.
  

•    */
  

•   if (xen_pv_domain() && !xen_initial_domain()) {
  

•           int level;
  

•           if (!lookup_address(vaddr, &level))
  

•                   goto err_free_area;
  

•   }
  

This activates my ancient allergies caused by the sprinkling "if (XEN)" randomly across the kernel tree. If this is a PV guest there probably should be a PV ioremap variant which hides all that gunk away...

Thx.