On Mon, Nov 25, 2013 at 06:43:13PM +0100, Paolo Bonzini wrote:
> 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>
BTW how about a unit-test for this?
Can be something along the lines of the acpi tests:
run BIOS, probe what it reported.
> ---
> 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
