void v3_print_mem_map(struct v3_vm_info * vm);
-
+uint32_t v3_get_max_page_size(struct guest_info * core, addr_t fault_addr, uint32_t req_size);
return 0;
}
- // Handle as a shadow large page if possible
- if (guest_pde->large_page
- && (info->vm_info->mem_align >= PAGE_SIZE_2MB)) {
- 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) == -1) {
- PrintError("Error handling large pagefault with large page\n");
- return -1;
- } else {
- return 0;
- }
- }
-
pte64_t * shadow_pt = NULL;
pte64_t * guest_pt = NULL;
// get the next shadow page level, allocate if not present
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)) {
+ // 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 (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;
+ } else {
+ PrintError("Error handling large pagefault with large page\n");
+ return -1;
+ }
+ } else {
+ PrintDebug("Underlying physical memory map doesn't allow use of a large page.\n");
+ }
+ // Fallthrough to handle the region with small pages
+ }
+
struct shadow_page_data * shdw_page = create_new_shadow_pt(info);
shadow_pt = (pte64_t *)V3_VAddr((void *)shdw_page->page_pa);
info->shdw_pg_mode = SHADOW_PAGING;
}
+
if (info->shdw_pg_mode == NESTED_PAGING) {
PrintDebug("Guest Paging Mode: NESTED_PAGING\n");
} else if (info->shdw_pg_mode == SHADOW_PAGING) {
PrintError("Guest paging mode incorrectly set.\n");
return -1;
}
+
+ if (strcasecmp(v3_cfg_val(pg_tree, "large_pages"), "true") == 0) {
+ info->use_large_pages = 1;
+ PrintDebug("Use of large pages in memory virtualization enabled.\n");
+ }
+
return 0;
}
// Reference: AMD Software Developer Manual Vol.2 Ch.5 "Page Translation and Protection"
-static uint32_t get_page_size(struct guest_info * core, addr_t fault_addr) {
- addr_t pg_start = 0UL, pg_end = 0UL; // 2MiB page containing the faulting address
- struct v3_mem_region * pg_next_reg = NULL; // next immediate mem reg after page start addr
- uint32_t page_size = PAGE_SIZE_4KB;
-
- /* If the guest has been configured for 2MiB pages, then we must check for hooked regions of
- * memory which may overlap with the 2MiB page containing the faulting address (due to
- * potentially differing access policies in place for e.g. i/o devices and APIC). A 2MiB page
- * can be used if a) no region overlaps the page [or b) a region does overlap but fully contains
- * the page]. The [bracketed] text pertains to the #if 0'd code below, state D. TODO modify this
- * note if someone decides to enable this optimization. It can be tested with the SeaStar
- * mapping.
- *
- * Examples: (CAPS regions are returned by v3_get_next_mem_region; state A returns the base reg)
- *
- * |region| |region| 2MiB mapped (state A)
- * |reg| |REG| 2MiB mapped (state B)
- * |region| |reg| |REG| |region| |reg| 4KiB mapped (state C)
- * |reg| |reg| |--REGION---| [2MiB mapped (state D)]
- * |--------------------------------------------| RAM
- * ^ fault addr
- * |----|----|----|----|----|page|----|----|----| 2MB pages
- * >>>>>>>>>>>>>>>>>>>> search space
- */
-
-
- // guest page maps to a host page + offset (so when we shift, it aligns with a host page)
- pg_start = PAGE_ADDR_2MB(fault_addr);
- pg_end = (pg_start + PAGE_SIZE_2MB);
-
- PrintDebug("%s: page [%p,%p) contains address\n", __FUNCTION__, (void *)pg_start, (void *)pg_end);
-
- pg_next_reg = v3_get_next_mem_region(core->vm_info, core->cpu_id, pg_start);
-
- if (pg_next_reg == NULL) {
- PrintError("%s: Error: address not in base region, %p\n", __FUNCTION__, (void *)fault_addr);
- return PAGE_SIZE_4KB;
- }
-
- if (pg_next_reg->flags.base == 1) {
- page_size = PAGE_SIZE_2MB; // State A
- } else {
-#if 0 // State B/C and D optimization
- if ((pg_next_reg->guest_end >= pg_end) &&
- ((pg_next_reg->guest_start >= pg_end) || (pg_next_reg->guest_start <= pg_start))) {
- page_size = PAGE_SIZE_2MB;
- }
-
- PrintDebug("%s: region [%p,%p) %s partially overlap with page\n", __FUNCTION__,
- (void *)pg_next_reg->guest_start, (void *)pg_next_reg->guest_end,
- (page_size == PAGE_SIZE_2MB) ? "does not" : "does");
-
-#else // State B/C
- if (pg_next_reg->guest_start >= pg_end) {
-
- page_size = PAGE_SIZE_2MB;
- }
-
- PrintDebug("%s: region [%p,%p) %s overlap with page\n", __FUNCTION__,
- (void *)pg_next_reg->guest_start, (void *)pg_next_reg->guest_end,
- (page_size == PAGE_SIZE_2MB) ? "does not" : "does");
-
-#endif
- }
-
- return page_size;
-}
-
-
static inline int handle_passthrough_pagefault_64(struct guest_info * core, addr_t fault_addr, pf_error_t error_code) {
pml4e64_t * pml = NULL;
pdpe64_t * pdpe = NULL;
* 2. the memory regions can be referenced by a large page
*/
if ((core->use_large_pages == 1) ) {
- page_size = get_page_size(core, fault_addr);
+ page_size = v3_get_max_page_size(core, fault_addr, PAGE_SIZE_2MB);
}
PrintDebug("Using page size of %dKB\n", page_size / 1024);
}
+// Determine if a given address can be handled by a large page of the requested size
+uint32_t v3_get_max_page_size(struct guest_info * core, addr_t fault_addr, uint32_t req_size) {
+ addr_t pg_start = 0UL, pg_end = 0UL; // large page containing the faulting addres
+ struct v3_mem_region * pg_next_reg = NULL; // next immediate mem reg after page start addr
+ uint32_t page_size = PAGE_SIZE_4KB;
+
+ /* If the guest has been configured for large pages, then we must check for hooked regions of
+ * memory which may overlap with the large page containing the faulting address (due to
+ * potentially differing access policies in place for e.g. i/o devices and APIC). A large page
+ * can be used if a) no region overlaps the page [or b) a region does overlap but fully contains
+ * the page]. The [bracketed] text pertains to the #if 0'd code below, state D. TODO modify this
+ * note if someone decides to enable this optimization. It can be tested with the SeaStar
+ * mapping.
+ *
+ * Examples: (CAPS regions are returned by v3_get_next_mem_region; state A returns the base reg)
+ *
+ * |region| |region| 2MiB mapped (state A)
+ * |reg| |REG| 2MiB mapped (state B)
+ * |region| |reg| |REG| |region| |reg| 4KiB mapped (state C)
+ * |reg| |reg| |--REGION---| [2MiB mapped (state D)]
+ * |--------------------------------------------| RAM
+ * ^ fault addr
+ * |----|----|----|----|----|page|----|----|----| 2MB pages
+ * >>>>>>>>>>>>>>>>>>>> search space
+ */
+
+
+ // guest page maps to a host page + offset (so when we shift, it aligns with a host page)
+ switch (req_size) {
+ case PAGE_SIZE_4KB:
+ return PAGE_SIZE_4KB;
+ case PAGE_SIZE_2MB:
+ pg_start = PAGE_ADDR_2MB(fault_addr);
+ pg_end = (pg_start + PAGE_SIZE_2MB);
+ break;
+ case PAGE_SIZE_4MB:
+ pg_start = PAGE_ADDR_4MB(fault_addr);
+ pg_end = (pg_start + PAGE_SIZE_4MB);
+ break;
+ case PAGE_SIZE_1GB:
+ pg_start = PAGE_ADDR_1GB(fault_addr);
+ pg_end = (pg_start + PAGE_SIZE_1GB);
+ break;
+ default:
+ PrintError("Invalid large page size requested.\n");
+ return -1;
+ }
+
+ PrintDebug("%s: page [%p,%p) contains address\n", __FUNCTION__, (void *)pg_start, (void *)pg_end);
+
+ pg_next_reg = v3_get_next_mem_region(core->vm_info, core->cpu_id, pg_start);
+
+ if (pg_next_reg == NULL) {
+ PrintError("%s: Error: address not in base region, %p\n", __FUNCTION__, (void *)fault_addr);
+ return PAGE_SIZE_4KB;
+ }
+
+ if (pg_next_reg->flags.base == 1) {
+ page_size = req_size; // State A
+ PrintDebug("%s: base region [%p,%p) contains page.\n", __FUNCTION__,
+ (void *)pg_next_reg->guest_start, (void *)pg_next_reg->guest_end);
+ } else {
+#if 0 // State B/C and D optimization
+ if ((pg_next_reg->guest_end >= pg_end) &&
+ ((pg_next_reg->guest_start >= pg_end) || (pg_next_reg->guest_start <= pg_start))) {
+ page_size = req_size;
+ }
+
+ PrintDebug("%s: region [%p,%p) %s partially overlap with page\n", __FUNCTION__,
+ (void *)pg_next_reg->guest_start, (void *)pg_next_reg->guest_end,
+ (page_size == req_size) ? "does not" : "does");
+
+#else // State B/C
+ if (pg_next_reg->guest_start >= pg_end) {
+
+ page_size = req_size;
+ }
+
+ PrintDebug("%s: region [%p,%p) %s overlap with page\n", __FUNCTION__,
+ (void *)pg_next_reg->guest_start, (void *)pg_next_reg->guest_end,
+ (page_size == req_size) ? "does not" : "does");
+
+#endif
+ }
+
+ return page_size;
+}
void v3_print_mem_map(struct v3_vm_info * vm) {
<vm class="PC">
<!-- Memory in MB -->
- <memory alignment="4KB">256</memory>
+ <memory alignment="2MB">256</memory>
<!-- Basic VMM system flags -->
<telemetry>enable</telemetry>
<paging mode="shadow">
<strategy>VTLB</strategy>
+ <large_pages/>
</paging>
<!--
<paging mode="nested">
- <pagesize>4KB</pagesize>
+ <large_pages/>
</paging>
-->
<schedule_hz>100</schedule_hz>
