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Re: [RFC PATCH v2 07/30] target/loongarch: Add MMU support for LoongArch
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From: |
Richard Henderson |
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Subject: |
Re: [RFC PATCH v2 07/30] target/loongarch: Add MMU support for LoongArch CPU. |
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Date: |
Thu, 11 Nov 2021 16:53:16 +0100 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 |
On 11/11/21 2:35 AM, Xiaojuan Yang wrote:
This patch introduces basic TLB interfaces.
Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>
---
target/loongarch/cpu-param.h | 3 +
target/loongarch/cpu.c | 36 ++++
target/loongarch/cpu.h | 57 ++++++
target/loongarch/internals.h | 7 +
target/loongarch/machine.c | 56 ++++++
target/loongarch/meson.build | 1 +
target/loongarch/tlb_helper.c | 339 ++++++++++++++++++++++++++++++++++
7 files changed, 499 insertions(+)
create mode 100644 target/loongarch/tlb_helper.c
diff --git a/target/loongarch/cpu-param.h b/target/loongarch/cpu-param.h
index 9a769b67e0..5a2147fb90 100644
--- a/target/loongarch/cpu-param.h
+++ b/target/loongarch/cpu-param.h
@@ -12,6 +12,9 @@
#define TARGET_PHYS_ADDR_SPACE_BITS 48
#define TARGET_VIRT_ADDR_SPACE_BITS 48
+#define TARGET_PHYS_MASK ((1UL << TARGET_PHYS_ADDR_SPACE_BITS) - 1)
+#define TARGET_VIRT_MASK ((1UL << TARGET_VIRT_ADDR_SPACE_BITS) - 1)
As before, unsigned long is wrong; use MAKE_64BIT_MASK.
These do not belong in cpu-param.h anyway; probably only tlb_helper.c needs
them.
+#ifndef CONFIG_USER_ONLY
+ qemu_fprintf(f, "EUEN 0x%lx\n", env->CSR_EUEN);
+ qemu_fprintf(f, "ESTAT 0x%lx\n", env->CSR_ESTAT);
+ qemu_fprintf(f, "ERA 0x%lx\n", env->CSR_ERA);
+ qemu_fprintf(f, "CRMD 0x%lx\n", env->CSR_CRMD);
+ qemu_fprintf(f, "PRMD 0x%lx\n", env->CSR_PRMD);
+ qemu_fprintf(f, "BadVAddr 0x%lx\n", env->CSR_BADV);
+ qemu_fprintf(f, "TLB refill ERA 0x%lx\n", env->CSR_TLBRERA);
+ qemu_fprintf(f, "TLB refill BadV 0x%lx\n", env->CSR_TLBRBADV);
+ qemu_fprintf(f, "EENTRY 0x%lx\n", env->CSR_EENTRY);
+ qemu_fprintf(f, "BadInstr 0x%lx\n", env->CSR_BADI);
+ qemu_fprintf(f, "PRCFG1 0x%lx\nPRCFG2 0x%lx\nPRCFG3 0x%lx\n",
+ env->CSR_PRCFG1, env->CSR_PRCFG3, env->CSR_PRCFG3);
%lx is wrong; use PRIx64.
+#define LOONGARCH_TLB_MAX 2112 /* 2048 STLB + 64 MTLB */
Better to write (2048 + 64).
+FIELD(TLB_MISC, E, 0, 1)
+FIELD(TLB_MISC, ASID, 1, 10)
+FIELD(TLB_MISC, G, 11, 1)
+FIELD(TLB_MISC, PS, 12, 6)
+FIELD(TLB_MISC, VPPN, 18, 35)
+
+/* Corresponding to CSR_TLBELO0/1 */
+FIELD(ENTRY0, V, 0, 1)
+FIELD(ENTRY0, D, 1, 1)
+FIELD(ENTRY0, NR, 2, 1)
+FIELD(ENTRY0, NX, 3, 1)
+FIELD(ENTRY0, MAT, 4, 2)
+FIELD(ENTRY0, PLV, 6, 2)
+FIELD(ENTRY0, RPLV, 8, 1)
+FIELD(ENTRY0, PPN, 9, 36)
+
+FIELD(ENTRY1, V, 0, 1)
+FIELD(ENTRY1, D, 1, 1)
+FIELD(ENTRY1, NR, 2, 1)
+FIELD(ENTRY1, NX, 3, 1)
+FIELD(ENTRY1, MAT, 4, 2)
+FIELD(ENTRY1, PLV, 6, 2)
+FIELD(ENTRY1, RPLV, 8, 1)
+FIELD(ENTRY1, PPN, 9, 36)
Why are you duplicating the CSR_TLBELO* fields?
+const VMStateInfo vmstate_info_tlb = {
+ .name = "tlb_entry",
+ .get = get_tlb,
+ .put = put_tlb,
+};
Better to use .fields.
+#define VMSTATE_TLB_ARRAY_V(_f, _s, _n, _v) \
+ VMSTATE_ARRAY(_f, _s, _n, _v, vmstate_info_tlb, loongarch_tlb)
+
+#define VMSTATE_TLB_ARRAY(_f, _s, _n) \
+ VMSTATE_TLB_ARRAY_V(_f, _s, _n, 0)
Don't need these.
+
+const VMStateDescription vmstate_tlb = {
+ .name = "cpu/tlb",
+ .version_id = 0,
+ .minimum_version_id = 0,
+ .fields = (VMStateField[]) {
+ VMSTATE_TLB_ARRAY(env.tlb, LoongArchCPU, LOONGARCH_TLB_MAX),
VMSTATE_STRUCT_ARRAY.
+ VMSTATE_END_OF_LIST()
+ }
+};
/* LoongArch CPU state */
@@ -22,6 +70,10 @@ const VMStateDescription vmstate_loongarch_cpu = {
VMSTATE_UINT64_ARRAY(env.fpr, LoongArchCPU, 32),
VMSTATE_UINT32(env.fcsr0, LoongArchCPU),
+ /* TLB */
+ VMSTATE_UINT32(env.stlb_size, LoongArchCPU),
+ VMSTATE_UINT32(env.mtlb_size, LoongArchCPU),
Might as well keep these in vmstate_tlb.
+/* TLB address map */
+static int loongarch_map_tlb_entry(CPULoongArchState *env, hwaddr *physical,
+ int *prot, target_ulong address,
+ int access_type, loongarch_tlb *tlb)
+{
+ uint64_t plv = FIELD_EX64(env->CSR_CRMD, CSR_CRMD, PLV);
Incorrect. PLV associated with mmu_idx, so you need to use that.
+ uint8_t tlb_ps, n, tlb_v0, tlb_v1, tlb_d0, tlb_d1;
+ uint8_t tlb_nx0, tlb_nx1, tlb_nr0, tlb_nr1;
+ uint64_t tlb_ppn0, tlb_ppn1;
+ uint8_t tlb_rplv0, tlb_rplv1, tlb_plv0, tlb_plv1;
+
+ tlb_ps = FIELD_EX64(tlb->tlb_misc, TLB_MISC, PS);
+ n = (address >> tlb_ps) & 0x1;/* Odd or even */
Surely you need to pass in tlb_ps, since it's not present in the STLB entries.
+
+ tlb_v0 = FIELD_EX64(tlb->tlb_entry0, ENTRY0, V);
+ tlb_d0 = FIELD_EX64(tlb->tlb_entry0, ENTRY0, D);
+ tlb_plv0 = FIELD_EX64(tlb->tlb_entry0, ENTRY0, PLV);
+ tlb_ppn0 = FIELD_EX64(tlb->tlb_entry0, ENTRY0, PPN);
+ tlb_nx0 = FIELD_EX64(tlb->tlb_entry0, ENTRY0, NX);
+ tlb_nr0 = FIELD_EX64(tlb->tlb_entry0, ENTRY0, NR);
+ tlb_rplv0 = FIELD_EX64(tlb->tlb_entry0, ENTRY0, RPLV);
+
+ tlb_v1 = FIELD_EX64(tlb->tlb_entry1, ENTRY1, V);
+ tlb_d1 = FIELD_EX64(tlb->tlb_entry1, ENTRY1, D);
+ tlb_plv1 = FIELD_EX64(tlb->tlb_entry1, ENTRY1, PLV);
+ tlb_ppn1 = FIELD_EX64(tlb->tlb_entry1, ENTRY1, PPN);
+ tlb_nx1 = FIELD_EX64(tlb->tlb_entry1, ENTRY1, NX);
+ tlb_nr1 = FIELD_EX64(tlb->tlb_entry1, ENTRY1, NR);
+ tlb_rplv1 = FIELD_EX64(tlb->tlb_entry1, ENTRY1, RPLV);
Better to check N first.
entry = n ? tlb->tlb_entry1 : tlb->tlb_entry0;
v = FIELD_EX64(entry, TLBENTRY, V);
etc.
+ *physical = (tlb_ppn1 << 12) | (address & ((1 << tlb_ps) - 1));
TARGET_PAGE_SIZE.
+/* LoongArch 3A5000 -style MMU emulation */
There's no mention of 3A5000 in "LoongArch Reference Manual", which defines this. I think
you've copied this from MIPS, which talks about r4k here.
+static int loongarch_map_address(CPULoongArchState *env, hwaddr *physical,
+ int *prot,
+ target_ulong address,
+ MMUAccessType access_type)
+{
+ loongarch_tlb *tlb;
+ uint16_t csr_asid, tlb_asid, stlb_idx;
+ uint8_t tlb_e, stlb_ps, tlb_ps, tlb_g;
+ int i, stlb_size, mtlb_size;
+ uint64_t vpn, tlb_vppn; /* Address to map */
+
+ stlb_size = env->stlb_size;
+ mtlb_size = env->mtlb_size;
+ csr_asid = FIELD_EX64(env->CSR_ASID, CSR_ASID, ASID);
+
+ /* Search MTLB */
+ for (i = stlb_size; i < stlb_size + mtlb_size; ++i) {
Bit of a shame to have a linear search. I guess it's ok for a start, but you'll find that
this function is critical to the emulation speed of qemu, so you should think about other
ways to organize the data.
+ tlb = &env->tlb[i];
+ tlb_vppn = FIELD_EX64(tlb->tlb_misc, TLB_MISC, VPPN);
+ tlb_ps = FIELD_EX64(tlb->tlb_misc, TLB_MISC, PS);
+
+ vpn = (address & TARGET_VIRT_MASK) >> (tlb_ps + 1);
Why +1?
+ tlb_asid = FIELD_EX64(tlb->tlb_misc, TLB_MISC, ASID);
+ tlb_e = FIELD_EX64(tlb->tlb_misc, TLB_MISC, E);
+ tlb_g = FIELD_EX64(tlb->tlb_misc, TLB_MISC, G);
+
+ if ((tlb_g == 1 || tlb_asid == csr_asid) &&
+ (vpn == (tlb_vppn >> (tlb_ps + 1 - 13))) && tlb_e) {
Surely extract and test the enable bit E before anything else, just to speed up
the lookup.
The -13 is a bit of a magic number. Surely TARGET_PAGE_BITS + 1.
+static int get_physical_address(CPULoongArchState *env, hwaddr *physical,
+ int *prot, target_ulong real_address,
+ MMUAccessType access_type, int mmu_idx)
+{
+ int user_mode = mmu_idx == LOONGARCH_HFLAG_UM;
+ int kernel_mode = !user_mode;
Incorrect. PLV == mmu_idx, as defined by cpu_mmu_index.
+ unsigned plv, base_c, base_v, tmp;
+ uint64_t pg = FIELD_EX64(env->CSR_CRMD, CSR_CRMD, PG);
+
+ /* Effective address */
+ target_ulong address = real_address;
+
+ /* Check PG */
+ if (!pg) {
+ /* DA mode */
+ *physical = address & TARGET_PHYS_MASK;
+ *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
+ return TLBRET_MATCH;
+ }
You need to define a fifth mmu_index for paging disabled, because the software tlb handler
runs in this mode. If you don't define that, you'll have to flush the softmmu tlb every
time you have a tlb miss.
+ plv = kernel_mode | (user_mode << 3);
plv_mask = 1 << plv;
+ base_v = address >> CSR_DMW_BASE_SH;
+ /* Check direct map window 0 */
+ base_c = env->CSR_DMWIN0 >> CSR_DMW_BASE_SH;
+ if ((plv & env->CSR_DMWIN0) && (base_c == base_v)) {
+ *physical = dmwin_va2pa(address);
+ *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
+ return TLBRET_MATCH;
+ }
+ /* Check direct map window 1 */
+ base_c = env->CSR_DMWIN1 >> CSR_DMW_BASE_SH;
+ if ((plv & env->CSR_DMWIN1) && (base_c == base_v)) {
+ *physical = dmwin_va2pa(address);
+ *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
+ return TLBRET_MATCH;
+ }
There are more than 2 of these, which is why I suggested putting them in an array, so that
you can loop. Maybe pull this out to a separate function, like the tlb lookup?
+ /* Check valid extension */
+ tmp = address >> (TARGET_VIRT_ADDR_SPACE_BITS - 1);
+ if (!(tmp == 0 || tmp == 0x1ffff)) {
Better to cast to int64_t first, so that this becomes 0 or -1, without knowing that 64 -
TARGET_VIRT_ADDR_SPACE_BITS - 1 -> 0x1ffff.
+void loongarch_mmu_init(CPULoongArchState *env)
+{
+ /* Number of MTLB */
+ env->mtlb_size = 64;
+
+ /* Number of STLB */
+ env->stlb_size = 2048;
+
+ /* For 16KB, ps = 14, compare the bit [47:15] */
+ for (int i = 0; i < LOONGARCH_TLB_MAX; i++) {
+ env->tlb[i].tlb_misc = FIELD_DP64(env->tlb[i].tlb_misc, TLB_MISC, E,
0);
+ }
Just memset the whole thing?
+bool loongarch_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
+ MMUAccessType access_type, int mmu_idx,
+ bool probe, uintptr_t retaddr)
+{
+ LoongArchCPU *cpu = LOONGARCH_CPU(cs);
+ CPULoongArchState *env = &cpu->env;
+ hwaddr physical;
+ int prot;
+ int ret = TLBRET_BADADDR;
+
+ /* Data access */
+ /* XXX: put correct access by using cpu_restore_state() correctly */
+ ret = get_physical_address(env, &physical, &prot, address,
+ access_type, mmu_idx);
+ switch (ret) {
+ case TLBRET_MATCH:
+ qemu_log_mask(CPU_LOG_MMU,
+ "%s address=%" VADDR_PRIx " physical " TARGET_FMT_plx
+ " prot %d\n", __func__, address, physical, prot);
+ break;
+ default:
+ qemu_log_mask(CPU_LOG_MMU,
+ "%s address=%" VADDR_PRIx " ret %d\n", __func__, address,
+ ret);
+ break;
+ }
+ if (ret == TLBRET_MATCH) {
+ tlb_set_page(cs, address & TARGET_PAGE_MASK,
+ physical & TARGET_PAGE_MASK, prot,
+ mmu_idx, TARGET_PAGE_SIZE);
+ return true;
Merge the above switch into this?
+ }
+ if (probe) {
+ return false;
+ } else {
+ raise_mmu_exception(env, address, access_type, ret);
+ do_raise_exception(env, cs->exception_index, retaddr);
+ }
+}
r~
- Re: [RFC PATCH v2 02/30] target/loongarch: Add CSR registers definition, (continued)
[RFC PATCH v2 07/30] target/loongarch: Add MMU support for LoongArch CPU., Xiaojuan Yang, 2021/11/10
- Re: [RFC PATCH v2 07/30] target/loongarch: Add MMU support for LoongArch CPU.,
Richard Henderson <=
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[RFC PATCH v2 01/30] target/loongarch: Update README, Xiaojuan Yang, 2021/11/10
[RFC PATCH v2 10/30] target/loongarch: Add other core instructions support, Xiaojuan Yang, 2021/11/10