svn commit: r364339 - head/sys/amd64/vmm

[Peter Grehan]

Author: grehan
Date: Tue Aug 18 07:08:17 2020
New Revision: 364339
URL: https://svnweb.freebsd.org/changeset/base/364339

Log:
  Allow guest device MMIO access from bootmem memory segments.
  
  Recent versions of UEFI have moved local APIC timer initialization into
  the early SEC phase which runs out of ROM, prior to self-relocating
  into RAM. This results in a hypervisor exit.
  
  Currently bhyve prevents instruction emulation from segments that aren't
  marked as "sysmem" aka guest RAM, with the vm_gpa_hold() routine failing.
  However, there is no reason for this restriction: the hypervisor already
  controls whether EPT mappings are marked as executable.
  
  Fix by dropping the redundant check of sysmem.
  
  MFC after:	3 weeks
  Differential Revision:	https://reviews.freebsd.org/D25955

Modified:
  head/sys/amd64/vmm/vmm.c

Modified: head/sys/amd64/vmm/vmm.c
==============================================================================
--- head/sys/amd64/vmm/vmm.c	Tue Aug 18 06:55:12 2020	(r364338)
+++ head/sys/amd64/vmm/vmm.c	Tue Aug 18 07:08:17 2020	(r364339)
@@ -999,8 +999,7 @@ vm_gpa_hold(struct vm *vm, int vcpuid, vm_paddr_t gpa,
 	count = 0;
 	for (i = 0; i < VM_MAX_MEMMAPS; i++) {
 		mm = &vm->mem_maps[i];
-		if (sysmem_mapping(vm, mm) && gpa >= mm->gpa &&
-		    gpa < mm->gpa + mm->len) {
+		if (gpa >= mm->gpa && gpa < mm->gpa + mm->len) {
 			count = vm_fault_quick_hold_pages(&vm->vmspace->vm_map,
 			    trunc_page(gpa), PAGE_SIZE, reqprot, &m, 1);
 			break;