return 0;
}
+// For an address on a page of size page_size, compute the actual alignment
+// of the physical page it maps to
+int compute_physical_alignment(addr_t va, addr_t pa, uint32_t page_size)
+{
+ addr_t va_offset, pa_base;
+ switch (page_size) {
+ case PAGE_SIZE_1GB:
+ va_offset = PAGE_OFFSET_1GB(va);
+ break;
+ case PAGE_SIZE_4MB:
+ va_offset = PAGE_OFFSET_4MB(va);
+ break;
+ case PAGE_SIZE_2MB:
+ va_offset = PAGE_OFFSET_2MB(va);
+ break;
+ case PAGE_SIZE_4KB:
+ return 1;
+ default:
+ PrintError("Invalid page size in %s.\n", __FUNCTION__);
+ return 0;
+ }
+
+ pa_base = pa - va_offset;
+
+ if (PAGE_OFFSET_1GB(pa_base) == 0) {
+ return PAGE_SIZE_1GB;
+ } else if (PAGE_OFFSET_4MB(pa_base) == 0) {
+ return PAGE_SIZE_4MB;
+ } else if (PAGE_OFFSET_2MB(pa_base) == 0) {
+ return PAGE_SIZE_2MB;
+ } else if (PAGE_OFFSET_4KB(pa_base) == 0) {
+ return PAGE_SIZE_4KB;
+ } else {
+ PrintError("Incorrection alignment setup or calculation in %s.\n", __FUNCTION__);
+ return 0;
+ }
+}
static int handle_pde_shadow_pagefault_64(struct guest_info * info, addr_t fault_addr, pf_error_t error_code,
pde64_t * shadow_pd, pde64_t * guest_pd) {
if (shadow_pde_access == PT_ACCESS_NOT_PRESENT) {
// Check if we can use large pages and the guest memory is properly aligned
// to potentially use a large page
- if (info->use_large_pages && guest_pde->large_page
- && (info->vm_info->mem_align >= PAGE_SIZE_2MB)) {
+ if (info->use_large_pages && guest_pde->large_page) {
// Check underlying physical memory map to see if a large page is viable
addr_t guest_pa = BASE_TO_PAGE_ADDR_2MB(((pde64_2MB_t *)guest_pde)->page_base_addr);
- uint32_t max_size = v3_get_max_page_size(info, guest_pa, PAGE_SIZE_2MB);
- if (max_size >= PAGE_SIZE_2MB) {
+ if ((compute_physical_alignment(fault_addr, guest_pa, PAGE_SIZE_2MB) >= PAGE_SIZE_2MB)
+ && (v3_get_max_page_size(info, guest_pa, PAGE_SIZE_2MB) >= PAGE_SIZE_2MB)) {
+ // should be able to use a large page.
if (handle_2MB_shadow_pagefault_pde_64(info, fault_addr, error_code, shadow_pde_access,
(pde64_2MB_t *)shadow_pde, (pde64_2MB_t *)guest_pde) == 0) {
return 0;
return -1;
}
} else {
- PrintDebug("Underlying physical memory map doesn't allow use of a large page.\n");
+ PrintDebug("Alignment or underlying physical memory map doesn't allow use of a large page.\n");
}
// Fallthrough to handle the region with small pages
}