hv: do EPT mapping only for physical memory backed GPA on pre-launched VMs

Currently for pre-launched VMs, HV intends to do EPT mapping for all GPA
space, which implies that it wastes HPA to back PCI hole and other vE820
entries that are not backed by physical memory.

This patch solves this issue and fixes ve820 entries whose length is not
aligned to 4K, and changes the lowmem entry's start GPA from 1MB to 2MB.

Tracked-On: #2587
Signed-off-by: Zide Chen <zide.chen@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>

Author: ZideChen0

hypervisor/arch/x86/configs/apl-mrb/ve820.c

@@ -7,33 +7,33 @@
 #include <e820.h>
 
 const struct e820_entry ve820_entry[E820_MAX_ENTRIES] = {
-	{	/* 0 to mptable */
+	{	/* usable RAM under 1MB */
 		.baseaddr = 0x0UL,
-		.length   = 0xEFFFFUL,
+		.length   = 0xF0000UL,		/* 960KB */
 		.type     = E820_TYPE_RAM
 	},
 
-	{	/* mptable 65536U */
-		.baseaddr = 0xF0000UL,
-		.length   = 0x10000UL,
+	{	/* mptable */
+		.baseaddr = 0xF0000UL,		/* 960KB */
+		.length   = 0x10000UL,		/* 16KB */
 		.type     = E820_TYPE_RESERVED
 	},
 
-	{	/* mptable to lowmem */
-		.baseaddr = 0x100000UL,
-		.length   = 0x1FF00000UL,
+	{	/* lowmem */
+		.baseaddr = 0x200000UL,		/* 2MB */
+		.length   = 0x1FE00000UL,	/* 510MB */
 		.type     = E820_TYPE_RAM
 	},
 
-	{	/* lowmem to PCI hole */
-		.baseaddr = 0x20000000UL,
-		.length   = 0xa0000000UL,
+	{	/* between lowmem and PCI hole */
+		.baseaddr = 0x20000000UL,	/* 512MB */
+		.length   = 0xA0000000UL,	/* 2560MB */
 		.type     = E820_TYPE_RESERVED
 	},
 
-	{	/* PCI hole to 4G */
-		.baseaddr = 0xe0000000UL,
-		.length   = 0x20000000UL,
+	{	/* between PCI hole and 4GB */
+		.baseaddr = 0xe0000000UL,	/* 3.5GB */
+		.length   = 0x20000000UL,	/* 512MB */
 		.type     = E820_TYPE_RESERVED
 	},
 };

hypervisor/arch/x86/configs/dnv-cb2/ve820.c

@@ -7,33 +7,33 @@
 #include <e820.h>
 
 const struct e820_entry ve820_entry[E820_MAX_ENTRIES] = {
-	{	/* 0 to mptable */
+	{	/* usable RAM under 1MB */
 		.baseaddr = 0x0UL,
-		.length   = 0xEFFFFUL,
+		.length   = 0xF0000UL,		/* 960KB */
 		.type     = E820_TYPE_RAM
 	},
 
-	{	/* mptable 65536U */
-		.baseaddr = 0xF0000UL,
-		.length   = 0x10000UL,
+	{	/* mptable */
+		.baseaddr = 0xF0000UL,		/* 960KB */
+		.length   = 0x10000UL,		/* 16KB */
 		.type     = E820_TYPE_RESERVED
 	},
 
-	{	/* mptable to lowmem */
-		.baseaddr = 0x100000UL,
-		.length   = 0x7FF00000UL,
+	{	/* lowmem */
+		.baseaddr = 0x200000UL,		/* 2MB */
+		.length   = 0x7FE00000UL,	/* 2046MB */
 		.type     = E820_TYPE_RAM
 	},
 
-	{	/* lowmem to PCI hole */
-		.baseaddr = 0x80000000UL,
-		.length   = 0x40000000UL,
+	{	/* between lowmem and PCI hole */
+		.baseaddr = 0x80000000UL,	/* 2GB */
+		.length   = 0x40000000UL,	/* 1GB */
 		.type     = E820_TYPE_RESERVED
 	},
 
-	{	/* PCI hole to 4G */
-		.baseaddr = 0xe0000000UL,
-		.length   = 0x20000000UL,
+	{	/* between PCI hole and 4GB */
+		.baseaddr = 0xe0000000UL,	/* 3.5GB */
+		.length   = 0x20000000UL,	/* 512MB */
 		.type     = E820_TYPE_RESERVED
 	},
 };

hypervisor/arch/x86/guest/vm.c

@@ -141,6 +141,39 @@ static void create_prelaunched_vm_e820(struct acrn_vm *vm)
 	vm->e820_entry_num = E820_MAX_ENTRIES;
 	vm->e820_entries = (struct e820_entry *)ve820_entry;
 }
+
+/**
+ * @pre vm != NULL && vm_config != NULL
+ */
+static void prepare_prelaunched_vm_memmap(struct acrn_vm *vm, const struct acrn_vm_config *vm_config)
+{
+	uint64_t base_hpa = vm_config->memory.start_hpa;
+	uint32_t i;
+
+	for (i = 0U; i < vm->e820_entry_num; i++) {
+		struct e820_entry *entry = &(vm->e820_entries[i]);
+
+		if (entry->length == 0UL) {
+			break;
+		}
+
+		/* Do EPT mapping for GPAs that are backed by physical memory */
+		if (entry->type == E820_TYPE_RAM) {
+			ept_mr_add(vm, (uint64_t *)vm->arch_vm.nworld_eptp, base_hpa, entry->baseaddr,
+				entry->length, EPT_RWX | EPT_WB);
+
+			base_hpa += entry->length;
+		}
+
+		/* GPAs under 1MB are always backed by physical memory */
+		if ((entry->type != E820_TYPE_RAM) && (entry->baseaddr < (uint64_t)MEM_1M)) {
+			ept_mr_add(vm, (uint64_t *)vm->arch_vm.nworld_eptp, base_hpa, entry->baseaddr,
+				entry->length, EPT_RWX | EPT_UNCACHED);
+
+			base_hpa += entry->length;
+		}
+	}
+}
 #endif
 
 /**
@@ -324,9 +357,7 @@ int32_t create_vm(uint16_t vm_id, struct acrn_vm_config *vm_config, struct acrn_
 			&vm_config->GUID[0], sizeof(vm_config->GUID));
 #ifdef CONFIG_PARTITION_MODE
 		create_prelaunched_vm_e820(vm);
-		ept_mr_add(vm, (uint64_t *)vm->arch_vm.nworld_eptp,
-			vm_config->memory.start_hpa, 0UL, vm_config->memory.size,
-			EPT_RWX|EPT_WB);
+		prepare_prelaunched_vm_memmap(vm, vm_config);
 		(void)init_vm_boot_info(vm);
 #endif
 	}