On 28/3/25 18:55, Richard Henderson wrote:
Revert ee3863b9d41 and a08d60bc6c2b. The logic behind changing
the system page size because of what the Loongson kernel "prefers"
is flawed.
In the Loongson-2E manual, section 5.5, it is clear that the cpu
supports a 4k page size (along with many others). Therefore we
must continue to support a 4k page size.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
target/mips/cpu-param.h | 5 -----
hw/mips/fuloong2e.c | 1 -
hw/mips/loongson3_virt.c | 1 -
target/mips/tcg/system/cp0_helper.c | 7 +------
target/mips/tcg/system/tlb_helper.c | 2 +-
5 files changed, 2 insertions(+), 14 deletions(-)
diff --git a/hw/mips/fuloong2e.c b/hw/mips/fuloong2e.c
index 646044e274..2a8507b8b0 100644
--- a/hw/mips/fuloong2e.c
+++ b/hw/mips/fuloong2e.c
@@ -334,7 +334,6 @@ static void mips_fuloong2e_machine_init(MachineClass *mc)
mc->default_cpu_type = MIPS_CPU_TYPE_NAME("Loongson-2E");
mc->default_ram_size = 256 * MiB;
mc->default_ram_id = "fuloong2e.ram";
- mc->minimum_page_bits = 14;
machine_add_audiodev_property(mc);
}
fuloong2e machine uses a Loongson-2E CPU, which as the manual you
pointed out mentions, supports 4K pages.
diff --git a/hw/mips/loongson3_virt.c b/hw/mips/loongson3_virt.c
index db1cc51314..1da20dccec 100644
--- a/hw/mips/loongson3_virt.c
+++ b/hw/mips/loongson3_virt.c
@@ -677,7 +677,6 @@ static void loongson3v_machine_class_init(ObjectClass *oc,
void *data)
mc->max_cpus = LOONGSON_MAX_VCPUS;
mc->default_ram_id = "loongson3.highram";
mc->default_ram_size = 1600 * MiB;
- mc->minimum_page_bits = 14;
mc->default_nic = "virtio-net-pci";
}
loongson3v machine uses Loongson-3 series CPUs with TCG, or
Loongson-3A4000 with KVM.
The Loongson-3A1000 is based on a GS464 core, which does support
4K (chapter 3.5: PageMask register).
The Loongson-3A2000 and 3A3000 are based on a GS464E core, which
also supports 4K (chapter 7.7 PageMask Register).
Address page Mask. The address mask is used to control the size
of the page table stored in the page table entry. GS464E supports
4KB to 1GB page size increments of 4.
The Loongson-3A4000 is based on a GS464V core, for which I couldn't
find the full manual. Being a GS464 with vector capabilities ("The
memory functional unit of GS464V is similar with GS464") I'll assume
4K is also OK there.
(I'll amend that information to the commit description)
Reviewed-by: Philippe Mathieu-Daudé <phi...@linaro.org>
