v2: condition enablement of new mapping to new machine types (Paolo)
v3: fix changelog
v4: rebase
v5: ensure alignment of piecetwo on 2MB GPA (Igor)
do not register zero-sized piece-one (Igor)
v6: fix memory leak (Igor)
fix integer overflow (Igor)
----
Align guest physical address and host physical address
beyond guest 4GB on a 1GB boundary.
Otherwise 1GB TLBs cannot be cached for the range.
Signed-off-by: Marcelo Tosatti <mtosa...@redhat.com>
[Reorganize code, keep same logic. - Paolo]
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
hw/i386/pc.c | 67 +++++++++++++++++++++++++++++++++++++++++++------
hw/i386/pc_piix.c | 3 ++
hw/i386/pc_q35.c | 3 ++
include/hw/i386/pc.h | 1 +
4 files changed, 65 insertions(+), 9 deletions(-)
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 6c82ada..485b44d 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1148,8 +1148,10 @@ FWCfgState *pc_memory_init(MemoryRegion *system_memory,
{
int linux_boot, i;
MemoryRegion *ram, *option_rom_mr;
- MemoryRegion *ram_below_4g, *ram_above_4g;
+ MemoryRegion *ram_below_4g, *ram_above_4g_pieceone, *ram_above_4g_piecetwo;
FWCfgState *fw_cfg;
+ uint64_t holesize, pieceonesize, piecetwosize;
+ uint64_t memsize, align_offset;
linux_boot = (kernel_filename != NULL);
@@ -1157,26 +1159,73 @@ FWCfgState *pc_memory_init(MemoryRegion *system_memory,
* aliases to address portions of it, mostly for backwards compatibility
* with older qemus that used qemu_ram_alloc().
*/
+ memsize = below_4g_mem_size + above_4g_mem_size;
+ holesize = 0x100000000ULL - below_4g_mem_size;
+
+ /* If 1GB hugepages are used to back guest RAM, we want the
+ * physical address 4GB to map to 4GB in the RAM, so that
+ * memory beyond 4GB is aligned on a 1GB boundary, at the
+ * host physical address space. Thus, the ram block range
+ * [holestart, 4GB] is mapped to the last holesize bytes of RAM:
+ *
+ * 0 h 4G memsize-holesize
+ *
+ * contiguous-ram-block [xxxxxx][yyy][zzzzz]
+ * '-----------.
+ * guest-addr-space [xxxxxx] [zzzzz][yyy]
+ *
+ * This is only done in new-enough machine types, and of course
+ * it is only possible if the [zzzzz] block exists at all.
+ */
+ if (guest_info->gb_align && above_4g_mem_size > holesize) {
+ /* Round the allocation up to 2 MB to make [zzzzz]'s size
+ * aligned, removing the extra from the [yyy] piece.
+ */
+ align_offset = ROUND_UP(memsize, 1UL << 21) - memsize;
+ piecetwosize = holesize - align_offset;
+ } else {
+ /* There's no [zzzzz] piece, all memory above 4G starts
+ * at below_4g_mem_size in the RAM block. Also no need
+ * to align anything.
+ */
+ align_offset = 0;
+ piecetwosize = above_4g_mem_size;
+ }
+
ram = g_malloc(sizeof(*ram));
- memory_region_init_ram(ram, NULL, "pc.ram",
- below_4g_mem_size + above_4g_mem_size);
+ memory_region_init_ram(ram, NULL, "pc.ram", memsize + align_offset);
vmstate_register_ram_global(ram);
*ram_memory = ram;
+
ram_below_4g = g_malloc(sizeof(*ram_below_4g));
memory_region_init_alias(ram_below_4g, NULL, "ram-below-4g", ram,
0, below_4g_mem_size);
memory_region_add_subregion(system_memory, 0, ram_below_4g);
+
+ pieceonesize = above_4g_mem_size - piecetwosize;
+ if (pieceonesize) {
+ ram_above_4g_pieceone = g_malloc(sizeof(*ram_above_4g_pieceone));
+ memory_region_init_alias(ram_above_4g_pieceone, NULL,
+ "ram-above-4g-pieceone", ram,
+ 0x100000000ULL, pieceonesize);
+ memory_region_add_subregion(system_memory, 0x100000000ULL,
+ ram_above_4g_pieceone);
+ }
+ if (piecetwosize) {
+ ram_above_4g_piecetwo = g_malloc(sizeof(*ram_above_4g_piecetwo));
+ memory_region_init_alias(ram_above_4g_piecetwo, NULL,
+ "ram-above-4g-piecetwo", ram,
+ below_4g_mem_size, piecetwosize);
+ memory_region_add_subregion(system_memory,
+ 0x100000000ULL + pieceonesize,
+ ram_above_4g_piecetwo);
+ }
+
e820_add_entry(0, below_4g_mem_size, E820_RAM);
if (above_4g_mem_size > 0) {
- ram_above_4g = g_malloc(sizeof(*ram_above_4g));
- memory_region_init_alias(ram_above_4g, NULL, "ram-above-4g", ram,
- below_4g_mem_size, above_4g_mem_size);
- memory_region_add_subregion(system_memory, 0x100000000ULL,
- ram_above_4g);
e820_add_entry(0x100000000ULL, above_4g_mem_size, E820_RAM);
}
-
/* Initialize PC system firmware */
pc_system_firmware_init(rom_memory, guest_info->isapc_ram_fw);
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 36f2495..ca9bd2e 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -62,6 +62,7 @@ static bool has_pvpanic;
static bool has_pci_info;
static bool has_acpi_build = true;
static bool smbios_type1_defaults = true;
+static bool gb_align = true;
/* PC hardware initialisation */
static void pc_init1(QEMUMachineInitArgs *args,
@@ -130,6 +131,7 @@ static void pc_init1(QEMUMachineInitArgs *args,
guest_info->has_pci_info = has_pci_info;
guest_info->isapc_ram_fw = !pci_enabled;
+ guest_info->gb_align = gb_align;
if (smbios_type1_defaults) {
/* These values are guest ABI, do not change */
@@ -249,6 +251,7 @@ static void pc_init_pci(QEMUMachineInitArgs *args)
static void pc_compat_1_7(QEMUMachineInitArgs *args)
{
smbios_type1_defaults = false;
+ gb_align = false;
}
static void pc_compat_1_6(QEMUMachineInitArgs *args)
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 50ca458..89c7720 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -52,6 +52,7 @@ static bool has_pvpanic;
static bool has_pci_info;
static bool has_acpi_build = true;
static bool smbios_type1_defaults = true;
+static bool gb_align = true;
/* PC hardware initialisation */
static void pc_q35_init(QEMUMachineInitArgs *args)
@@ -115,6 +116,7 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
guest_info->has_pci_info = has_pci_info;
guest_info->isapc_ram_fw = false;
guest_info->has_acpi_build = has_acpi_build;
+ guest_info->gb_align = gb_align;
if (smbios_type1_defaults) {
/* These values are guest ABI, do not change */
@@ -233,6 +235,7 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
static void pc_compat_1_7(QEMUMachineInitArgs *args)
{
smbios_type1_defaults = false;
+ gb_align = false;
}
static void pc_compat_1_6(QEMUMachineInitArgs *args)
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 9af09d3..8047e82 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -41,6 +41,7 @@ struct PcGuestInfo {
uint64_t *node_cpu;
FWCfgState *fw_cfg;
bool has_acpi_build;
+ bool gb_align;
};
/* parallel.c */
--
1.7.1
