> -----Original Message-----
> From: Philippe Mathieu-Daudé <phi...@linaro.org>
> Sent: Wednesday, March 12, 2025 2:20 PM
> To: Brian Cain <brian.c...@oss.qualcomm.com>; qemu-devel@nongnu.org
> Cc: richard.hender...@linaro.org; Matheus Bernardino (QUIC)
> <quic_mathb...@quicinc.com>; a...@rev.ng; a...@rev.ng; Marco Liebel
> (QUIC) <quic_mlie...@quicinc.com>; ltaylorsimp...@gmail.com;
> alex.ben...@linaro.org; Mark Burton (QUIC)
> <quic_mbur...@quicinc.com>; Sid Manning <sidn...@quicinc.com>; Brian
> Cain <bc...@quicinc.com>; Michael Lambert <mlamb...@quicinc.com>
> Subject: Re: [PATCH 34/38] target/hexagon: Add initial MMU model
>
> WARNING: This email originated from outside of Qualcomm. Please be wary
> of any links or attachments, and do not enable macros.
>
> On 1/3/25 06:26, Brian Cain wrote:
> > From: Brian Cain <bc...@quicinc.com>
> >
> > Co-authored-by: Taylor Simpson <ltaylorsimp...@gmail.com>
> > Co-authored-by: Michael Lambert <mlamb...@quicinc.com>
> > Co-authored-by: Sid Manning <sidn...@quicinc.com>
> > Co-authored-by: Matheus Tavares Bernardino
> <quic_mathb...@quicinc.com>
> > Signed-off-by: Brian Cain <brian.c...@oss.qualcomm.com>
> > ---
> > target/hexagon/cpu-param.h | 4 +
> > target/hexagon/cpu.h | 13 +
> > target/hexagon/hex_mmu.h | 30 +++
> > target/hexagon/internal.h | 3 +
> > target/hexagon/cpu.c | 27 +-
> > target/hexagon/hex_mmu.c | 528
> +++++++++++++++++++++++++++++++++++++
> > target/hexagon/machine.c | 30 +++
> > target/hexagon/translate.c | 2 +-
> > target/hexagon/meson.build | 3 +-
> > 9 files changed, 637 insertions(+), 3 deletions(-)
> > create mode 100644 target/hexagon/hex_mmu.h
> > create mode 100644 target/hexagon/hex_mmu.c
>
>
> > diff --git a/target/hexagon/cpu.c b/target/hexagon/cpu.c index
> > 34c39cecd9..7ff678195d 100644
> > --- a/target/hexagon/cpu.c
> > +++ b/target/hexagon/cpu.c
> > @@ -28,6 +28,7 @@
> > #include "exec/gdbstub.h"
> > #include "cpu_helper.h"
> > #include "max.h"
> > +#include "hex_mmu.h"
> >
> > #ifndef CONFIG_USER_ONLY
> > #include "sys_macros.h"
> > @@ -283,6 +284,18 @@ static void
> hexagon_restore_state_to_opc(CPUState *cs,
> > cpu_env(cs)->gpr[HEX_REG_PC] = data[0];
> > }
> >
> > +
> > +#ifndef CONFIG_USER_ONLY
> > +static void mmu_reset(CPUHexagonState *env) {
> > + CPUState *cs = env_cpu(env);
> > + if (cs->cpu_index == 0) {
>
> This doesn't scale to heterogeneous emulation.
[Sid Manning]
Heterogeneous emulation, you mean a version of QEMU with something like ARM and
Hexagon configured to run concurrently?
I think we can substitute this with env->threadId, threadId is the same htid
(hardware thread id)
>
> > + memset(env->hex_tlb, 0, sizeof(*env->hex_tlb));
> > + }
> > +}
> > +#endif
> > +
> > +
> > static void hexagon_cpu_reset_hold(Object *obj, ResetType type)
> > {
> > CPUState *cs = CPU(obj);
> > @@ -310,6 +323,7 @@ static void hexagon_cpu_reset_hold(Object *obj,
> ResetType type)
> > if (cs->cpu_index == 0) {
> > arch_set_system_reg(env, HEX_SREG_MODECTL, 0x1);
> > }
> > + mmu_reset(env);
> > arch_set_system_reg(env, HEX_SREG_HTID, cs->cpu_index);
> > memset(env->t_sreg, 0, sizeof(target_ulong) * NUM_SREGS);
> > memset(env->greg, 0, sizeof(target_ulong) * NUM_GREGS); @@
> > -341,6 +355,14 @@ static void hexagon_cpu_realize(DeviceState *dev,
> Error **errp)
> > return;
> > }
> >
> > +#ifndef CONFIG_USER_ONLY
> > + HexagonCPU *cpu = HEXAGON_CPU(cs);
> > + if (cpu->num_tlbs > MAX_TLB_ENTRIES) {
> > + error_setg(errp, "Number of TLBs selected is invalid");
> > + return;
> > + }
> > +#endif
> > +
> > gdb_register_coprocessor(cs, hexagon_hvx_gdb_read_register,
> > hexagon_hvx_gdb_write_register,
> >
> > gdb_find_static_feature("hexagon-hvx.xml"), 0); @@ -352,9 +374,12 @@
> static void hexagon_cpu_realize(DeviceState *dev, Error **errp)
> > #endif
> >
> > qemu_init_vcpu(cs);
> > +#ifndef CONFIG_USER_ONLY
> > + CPUHexagonState *env = cpu_env(cs);
> > + hex_mmu_realize(env);
> > +#endif
> > cpu_reset(cs);
> > #ifndef CONFIG_USER_ONLY
> > - CPUHexagonState *env = cpu_env(cs);
> > if (cs->cpu_index == 0) {
> > env->g_sreg = g_new0(target_ulong, NUM_SREGS);
> > } else {
> > diff --git a/target/hexagon/hex_mmu.c b/target/hexagon/hex_mmu.c
> new
> > file mode 100644 index 0000000000..54c4ba2dbf
> > --- /dev/null
> > +++ b/target/hexagon/hex_mmu.c
> > @@ -0,0 +1,528 @@
> > +/*
> > + * Copyright(c) 2019-2025 Qualcomm Innovation Center, Inc. All Rights
> Reserved.
> > + *
> > + * SPDX-License-Identifier: GPL-2.0-or-later */
> > +
> > +#include "qemu/osdep.h"
> > +#include "qemu/main-loop.h"
> > +#include "qemu/qemu-print.h"
> > +#include "cpu.h"
> > +#include "system/cpus.h"
> > +#include "internal.h"
> > +#include "exec/exec-all.h"
> > +#include "hex_mmu.h"
> > +#include "macros.h"
> > +#include "sys_macros.h"
> > +#include "reg_fields.h"
> > +
> > +#define GET_TLB_FIELD(ENTRY, FIELD) \
> > + ((uint64_t)fEXTRACTU_BITS(ENTRY, reg_field_info[FIELD].width, \
> > + reg_field_info[FIELD].offset))
> > +
> > +/* PPD (physical page descriptor) */
> > +static inline uint64_t GET_PPD(uint64_t entry) {
> > + return GET_TLB_FIELD(entry, PTE_PPD) |
> > + (GET_TLB_FIELD(entry, PTE_PA35) <<
> > +reg_field_info[PTE_PPD].width); }
> > +
> > +#define NO_ASID (1 << 8)
> > +
> > +typedef enum {
> > + PGSIZE_4K,
> > + PGSIZE_16K,
> > + PGSIZE_64K,
> > + PGSIZE_256K,
> > + PGSIZE_1M,
> > + PGSIZE_4M,
> > + PGSIZE_16M,
> > + PGSIZE_64M,
> > + PGSIZE_256M,
> > + PGSIZE_1G,
> > + NUM_PGSIZE_TYPES
>
> Is NUM_PGSIZE_TYPES part of the enum?
[Sid Manning]
Could be, #define NUM_PGSIZE_TYPES (SHIFT_1G + 1)
Instead.
>
> > +} tlb_pgsize_t;
> > +
> > +static const char *pgsize_str[NUM_PGSIZE_TYPES] = {
> > + "4K",
> > + "16K",
> > + "64K",
> > + "256K",
> > + "1M",
> > + "4M",
> > + "16M",
> > + "64M",
> > + "256M",
> > + "1G",
> > +};
> > +
> > +#define INVALID_MASK 0xffffffffLL
> > +
> > +static const uint64_t encmask_2_mask[] = {
> > + 0x0fffLL, /* 4k, 0000 */
> > + 0x3fffLL, /* 16k, 0001 */
> > + 0xffffLL, /* 64k, 0010 */
> > + 0x3ffffLL, /* 256k, 0011 */
> > + 0xfffffLL, /* 1m, 0100 */
> > + 0x3fffffLL, /* 4m, 0101 */
> > + 0xffffffLL, /* 16m, 0110 */
> > + 0x3ffffffLL, /* 64m, 0111 */
> > + 0xfffffffLL, /* 256m, 1000 */
> > + 0x3fffffffLL, /* 1g, 1001 */
> > + INVALID_MASK, /* RSVD, 0111 */
> > +};
> > +
> > +/*
> > + * @return the page size type from @a entry.
> > + */
> > +static inline tlb_pgsize_t hex_tlb_pgsize_type(uint64_t entry) {
> > + if (entry == 0) {
> > + qemu_log_mask(CPU_LOG_MMU, "%s: Supplied TLB entry was 0!\n",
> __func__);
> > + return 0;
> > + }
> > + tlb_pgsize_t size = ctz64(entry);
> > + g_assert(size < NUM_PGSIZE_TYPES);
> > + return size;
> > +}
> > +
> > +/*
> > + * @return the page size of @a entry, in bytes.
> > + */
> > +static inline uint64_t hex_tlb_page_size_bytes(uint64_t entry) {
> > + return 1ull << (TARGET_PAGE_BITS + 2 *
> > +hex_tlb_pgsize_type(entry)); }
> > +
> > +static inline uint64_t hex_tlb_phys_page_num(uint64_t entry) {
> > + uint32_t ppd = GET_PPD(entry);
> > + return ppd >> 1;
> > +}
> > +
> > +static inline uint64_t hex_tlb_phys_addr(uint64_t entry) {
> > + uint64_t pagemask = encmask_2_mask[hex_tlb_pgsize_type(entry)];
> > + uint64_t pagenum = hex_tlb_phys_page_num(entry);
> > + uint64_t PA = (pagenum << TARGET_PAGE_BITS) & (~pagemask);
> > + return PA;
> > +}
> > +
> > +static inline uint64_t hex_tlb_virt_addr(uint64_t entry) {
> > + return (uint64_t)GET_TLB_FIELD(entry, PTE_VPN) <<
> > +TARGET_PAGE_BITS;
>
> return vaddr type?
Yeah, I think so.
>
> > +}
> > +
> > +static bool hex_dump_mmu_entry(FILE *f, uint64_t entry) {
> > + if (GET_TLB_FIELD(entry, PTE_V)) {
> > + fprintf(f, "0x%016" PRIx64 ": ", entry);
> > + uint64_t PA = hex_tlb_phys_addr(entry);
> > + uint64_t VA = hex_tlb_virt_addr(entry);
> > + fprintf(f, "V:%" PRId64 " G:%" PRId64 " A1:%" PRId64 " A0:%"
> > PRId64,
> > + GET_TLB_FIELD(entry, PTE_V), GET_TLB_FIELD(entry, PTE_G),
> > + GET_TLB_FIELD(entry, PTE_ATR1), GET_TLB_FIELD(entry,
> PTE_ATR0));
> > + fprintf(f, " ASID:0x%02" PRIx64 " VA:0x%08" PRIx64,
> > + GET_TLB_FIELD(entry, PTE_ASID), VA);
> > + fprintf(f,
> > + " X:%" PRId64 " W:%" PRId64 " R:%" PRId64 " U:%" PRId64
> > + " C:%" PRId64,
> > + GET_TLB_FIELD(entry, PTE_X), GET_TLB_FIELD(entry, PTE_W),
> > + GET_TLB_FIELD(entry, PTE_R), GET_TLB_FIELD(entry, PTE_U),
> > + GET_TLB_FIELD(entry, PTE_C));
> > + fprintf(f, " PA:0x%09" PRIx64 " SZ:%s (0x%" PRIx64 ")", PA,
> > + pgsize_str[hex_tlb_pgsize_type(entry)],
> > + hex_tlb_page_size_bytes(entry));
> > + fprintf(f, "\n");
> > + return true;
> > + }
> > +
> > + /* Not valid */
> > + return false;
> > +}
> > +
> > +void dump_mmu(CPUHexagonState *env)
> > +{
> > + int i;
> > +
> > + HexagonCPU *cpu = env_archcpu(env);
> > + for (i = 0; i < cpu->num_tlbs; i++) {
> > + uint64_t entry = env->hex_tlb->entries[i];
> > + if (GET_TLB_FIELD(entry, PTE_V)) {
> > + qemu_printf("0x%016" PRIx64 ": ", entry);
> > + uint64_t PA = hex_tlb_phys_addr(entry);
> > + uint64_t VA = hex_tlb_virt_addr(entry);
> > + qemu_printf(
> > + "V:%" PRId64 " G:%" PRId64 " A1:%" PRId64 " A0:%" PRId64,
> > + GET_TLB_FIELD(entry, PTE_V), GET_TLB_FIELD(entry, PTE_G),
> > + GET_TLB_FIELD(entry, PTE_ATR1), GET_TLB_FIELD(entry,
> PTE_ATR0));
> > + qemu_printf(" ASID:0x%02" PRIx64 " VA:0x%08" PRIx64,
> > + GET_TLB_FIELD(entry, PTE_ASID), VA);
> > + qemu_printf(
> > + " X:%" PRId64 " W:%" PRId64 " R:%" PRId64 " U:%" PRId64
> > + " C:%" PRId64,
> > + GET_TLB_FIELD(entry, PTE_X), GET_TLB_FIELD(entry, PTE_W),
> > + GET_TLB_FIELD(entry, PTE_R), GET_TLB_FIELD(entry, PTE_U),
> > + GET_TLB_FIELD(entry, PTE_C));
> > + qemu_printf(" PA:0x%09" PRIx64 " SZ:%s (0x%" PRIx64 ")", PA,
> > + pgsize_str[hex_tlb_pgsize_type(entry)],
> > + hex_tlb_page_size_bytes(entry));
> > + qemu_printf("\n");
> > + }
> > + }
> > +}
> > +
> > +static inline void hex_log_tlbw(uint32_t index, uint64_t entry) {
> > + if (qemu_loglevel_mask(CPU_LOG_MMU)) {
> > + if (qemu_log_enabled()) {
> > + FILE *logfile = qemu_log_trylock();
> > + if (logfile) {
> > + fprintf(logfile, "tlbw[%03d]: ", index);
> > + if (!hex_dump_mmu_entry(logfile, entry)) {
> > + fprintf(logfile, "invalid\n");
> > + }
> > + qemu_log_unlock(logfile);
> > + }
> > + }
> > + }
> > +}
> > +
> > +void hex_tlbw(CPUHexagonState *env, uint32_t index, uint64_t value) {
> > + uint32_t myidx = fTLB_NONPOW2WRAP(fTLB_IDXMASK(index));
> > + bool old_entry_valid = GET_TLB_FIELD(env->hex_tlb->entries[myidx],
> PTE_V);
> > + if (old_entry_valid && hexagon_cpu_mmu_enabled(env)) {
> > + CPUState *cs = env_cpu(env);
> > +
> > + tlb_flush(cs);
> > + }
> > + env->hex_tlb->entries[myidx] = (value);
> > + hex_log_tlbw(myidx, value);
> > +}
> > +
> > +void hex_mmu_realize(CPUHexagonState *env) {
> > + CPUState *cs = env_cpu(env);
> > + if (cs->cpu_index == 0) {
>
> Problem with heterogeneous emulation.
>
> > + env->hex_tlb = g_malloc0(sizeof(CPUHexagonTLBContext));
> > + } else {
> > + CPUState *cpu0_s = NULL;
> > + CPUHexagonState *env0 = NULL;
> > + CPU_FOREACH(cpu0_s) {
> > + assert(cpu0_s->cpu_index == 0);
> > + env0 = &(HEXAGON_CPU(cpu0_s)->env);
> > + break;
> > + }
> > + env->hex_tlb = env0->hex_tlb;
> > + }
> > +}
> > +
> > +void hex_mmu_on(CPUHexagonState *env) {
> > + CPUState *cs = env_cpu(env);
> > + qemu_log_mask(CPU_LOG_MMU, "Hexagon MMU turned on!\n");
> > + tlb_flush(cs);
> > +}
> > +
> > +void hex_mmu_off(CPUHexagonState *env) {
> > + CPUState *cs = env_cpu(env);
> > + qemu_log_mask(CPU_LOG_MMU, "Hexagon MMU turned off!\n");
> > + tlb_flush(cs);
> > +}
> > +
> > +void hex_mmu_mode_change(CPUHexagonState *env) {
> > + qemu_log_mask(CPU_LOG_MMU, "Hexagon mode change!\n");
> > + CPUState *cs = env_cpu(env);
> > + tlb_flush(cs);
> > +}
> > +
> > +static inline bool hex_tlb_entry_match_noperm(uint64_t entry, uint32_t
> asid,
> > + uint64_t VA) {
> > + if (GET_TLB_FIELD(entry, PTE_V)) {
> > + if (GET_TLB_FIELD(entry, PTE_G)) {
> > + /* Global entry - ingnore ASID */
> > + } else if (asid != NO_ASID) {
> > + uint32_t tlb_asid = GET_TLB_FIELD(entry, PTE_ASID);
> > + if (tlb_asid != asid) {
> > + return false;
> > + }
> > + }
> > +
> > + uint64_t page_size = hex_tlb_page_size_bytes(entry);
> > + uint64_t page_start =
> > + ROUND_DOWN(hex_tlb_virt_addr(entry), page_size);
> > + if (page_start <= VA && VA < page_start + page_size) {
> > + return true;
> > + }
> > + }
> > + return false;
> > +}
> > +
> > +static inline void hex_tlb_entry_get_perm(CPUHexagonState *env,
> uint64_t entry,
> > + MMUAccessType access_type,
> > + int mmu_idx, int *prot,
> > + int32_t *excp) {
> > + g_assert_not_reached();
> > +}
> > +
> > +static inline bool hex_tlb_entry_match(CPUHexagonState *env, uint64_t
> entry,
> > + uint8_t asid, target_ulong VA,
> > + MMUAccessType access_type, hwaddr
> > *PA,
> > + int *prot, int *size, int32_t *excp,
> > + int mmu_idx) {
> > + if (hex_tlb_entry_match_noperm(entry, asid, VA)) {
> > + hex_tlb_entry_get_perm(env, entry, access_type, mmu_idx, prot,
> excp);
> > + *PA = hex_tlb_phys_addr(entry);
> > + *size = hex_tlb_page_size_bytes(entry);
> > + return true;
> > + }
> > + return false;
> > +}
> > +
> > +bool hex_tlb_find_match(CPUHexagonState *env, target_ulong VA,
> > + MMUAccessType access_type, hwaddr *PA, int *prot,
> > + int *size, int32_t *excp, int mmu_idx) {
> > + *PA = 0;
> > + *prot = 0;
> > + *size = 0;
> > + *excp = 0;
> > + uint32_t ssr = arch_get_system_reg(env, HEX_SREG_SSR);
> > + uint8_t asid = GET_SSR_FIELD(SSR_ASID, ssr);
> > + int i;
> > + HexagonCPU *cpu = env_archcpu(env);
> > + for (i = 0; i < cpu->num_tlbs; i++) {
> > + uint64_t entry = env->hex_tlb->entries[i];
> > + if (hex_tlb_entry_match(env, entry, asid, VA, access_type, PA,
> > prot,
> > + size, excp, mmu_idx)) {
> > + return true;
> > + }
> > + }
> > + return false;
> > +}
> > +
> > +static uint32_t hex_tlb_lookup_by_asid(CPUHexagonState *env, uint32_t
> asid,
> > + uint32_t VA) {
> > + g_assert_not_reached();
> > +}
> > +
> > +/* Called from tlbp instruction */
> > +uint32_t hex_tlb_lookup(CPUHexagonState *env, uint32_t ssr, uint32_t
> > +VA) {
> > + return hex_tlb_lookup_by_asid(env, GET_SSR_FIELD(SSR_ASID, ssr),
> > +VA); }
> > +
> > +static bool hex_tlb_is_match(CPUHexagonState *env,
> > + uint64_t entry1, uint64_t entry2,
> > + bool consider_gbit) {
> > + bool valid1 = GET_TLB_FIELD(entry1, PTE_V);
> > + bool valid2 = GET_TLB_FIELD(entry2, PTE_V);
> > + uint64_t size1 = hex_tlb_page_size_bytes(entry1);
> > + uint64_t vaddr1 = ROUND_DOWN(hex_tlb_virt_addr(entry1), size1);
> > + uint64_t size2 = hex_tlb_page_size_bytes(entry2);
> > + uint64_t vaddr2 = ROUND_DOWN(hex_tlb_virt_addr(entry2), size2);
> > + int asid1 = GET_TLB_FIELD(entry1, PTE_ASID);
> > + int asid2 = GET_TLB_FIELD(entry2, PTE_ASID);
> > + bool gbit1 = GET_TLB_FIELD(entry1, PTE_G);
> > + bool gbit2 = GET_TLB_FIELD(entry2, PTE_G);
> > +
> > + if (!valid1 || !valid2) {
> > + return false;
> > + }
> > +
> > + if (((vaddr1 <= vaddr2) && (vaddr2 < (vaddr1 + size1))) ||
> > + ((vaddr2 <= vaddr1) && (vaddr1 < (vaddr2 + size2)))) {
> > + if (asid1 == asid2) {
> > + return true;
> > + }
> > + if ((consider_gbit && gbit1) || gbit2) {
> > + return true;
> > + }
> > + }
> > + return false;
> > +}
> > +
> > +/*
> > + * Return codes:
> > + * 0 or positive index of match
> > + * -1 multiple matches
> > + * -2 no match
> > + */
> > +int hex_tlb_check_overlap(CPUHexagonState *env, uint64_t entry,
> > +uint64_t index) {
> > + int matches = 0;
> > + int last_match = 0;
> > + int i;
> > +
> > + HexagonCPU *cpu = env_archcpu(env);
> > + for (i = 0; i < cpu->num_tlbs; i++) {
> > + if (hex_tlb_is_match(env, entry, env->hex_tlb->entries[i], false))
> > {
> > + matches++;
> > + last_match = i;
> > + }
> > + }
> > +
> > + if (matches == 1) {
> > + return last_match;
> > + }
> > + if (matches == 0) {
> > + return -2;
> > + }
> > + return -1;
> > +}
> > +
> > +static inline void print_thread(const char *str, CPUState *cs) {
> > + g_assert(bql_locked());
> > + CPUHexagonState *thread = cpu_env(cs);
> > + bool is_stopped = cpu_is_stopped(cs);
> > + int exe_mode = get_exe_mode(thread);
> > + hex_lock_state_t lock_state = thread->tlb_lock_state;
> > + qemu_log_mask(CPU_LOG_MMU,
> > + "%s: threadId = %d: %s, exe_mode = %s, tlb_lock_state = %s\n",
> > + str,
> > + thread->threadId,
> > + is_stopped ? "stopped" : "running",
> > + exe_mode == HEX_EXE_MODE_OFF ? "off" :
> > + exe_mode == HEX_EXE_MODE_RUN ? "run" :
> > + exe_mode == HEX_EXE_MODE_WAIT ? "wait" :
> > + exe_mode == HEX_EXE_MODE_DEBUG ? "debug" :
> > + "unknown",
> > + lock_state == HEX_LOCK_UNLOCKED ? "unlocked" :
> > + lock_state == HEX_LOCK_WAITING ? "waiting" :
> > + lock_state == HEX_LOCK_OWNER ? "owner" :
> > + "unknown");
> > +}
> > +
> > +static inline void print_thread_states(const char *str) {
> > + CPUState *cs;
> > + CPU_FOREACH(cs) {
>
> Ditto heterogeneous emulation.
OK, we could pass CPUHexagonState and do the following:
static inline void print_thread_states(CPUHexagonState *env, const char *str)
{
CPUState *cs = env_cpu(env);
CPU_FOREACH(cs) {
print_thread(str, cs);
}
}
>
> > + print_thread(str, cs);
> > + }
> > +}
> > +
> > +void hex_tlb_lock(CPUHexagonState *env) {
> > + qemu_log_mask(CPU_LOG_MMU, "hex_tlb_lock: %d\n", env-
> >threadId);
> > + BQL_LOCK_GUARD();
> > + g_assert((env->tlb_lock_count == 0) || (env->tlb_lock_count ==
> > +1));
> > +
> > + uint32_t syscfg = arch_get_system_reg(env, HEX_SREG_SYSCFG);
> > + uint8_t tlb_lock = GET_SYSCFG_FIELD(SYSCFG_TLBLOCK, syscfg);
> > + if (tlb_lock) {
> > + if (env->tlb_lock_state == HEX_LOCK_QUEUED) {
> > + env->next_PC += 4;
> > + env->tlb_lock_count++;
> > + env->tlb_lock_state = HEX_LOCK_OWNER;
> > + SET_SYSCFG_FIELD(env, SYSCFG_TLBLOCK, 1);
> > + return;
> > + }
> > + if (env->tlb_lock_state == HEX_LOCK_OWNER) {
> > + qemu_log_mask(CPU_LOG_MMU | LOG_GUEST_ERROR,
> > + "Double tlblock at PC: 0x%x, thread may hang\n",
> > + env->next_PC);
> > + env->next_PC += 4;
> > + CPUState *cs = env_cpu(env);
> > + cpu_interrupt(cs, CPU_INTERRUPT_HALT);
> > + return;
> > + }
> > + env->tlb_lock_state = HEX_LOCK_WAITING;
> > + CPUState *cs = env_cpu(env);
> > + cpu_interrupt(cs, CPU_INTERRUPT_HALT);
> > + } else {
> > + env->next_PC += 4;
> > + env->tlb_lock_count++;
> > + env->tlb_lock_state = HEX_LOCK_OWNER;
> > + SET_SYSCFG_FIELD(env, SYSCFG_TLBLOCK, 1);
> > + }
> > +
> > + if (qemu_loglevel_mask(CPU_LOG_MMU)) {
> > + qemu_log_mask(CPU_LOG_MMU, "Threads after hex_tlb_lock:\n");
> > + print_thread_states("\tThread");
> > + }
> > +}
> > +
> > +void hex_tlb_unlock(CPUHexagonState *env) {
> > + BQL_LOCK_GUARD();
> > + g_assert((env->tlb_lock_count == 0) || (env->tlb_lock_count ==
> > +1));
> > +
> > + /* Nothing to do if the TLB isn't locked by this thread */
> > + uint32_t syscfg = arch_get_system_reg(env, HEX_SREG_SYSCFG);
> > + uint8_t tlb_lock = GET_SYSCFG_FIELD(SYSCFG_TLBLOCK, syscfg);
> > + if ((tlb_lock == 0) ||
> > + (env->tlb_lock_state != HEX_LOCK_OWNER)) {
> > + qemu_log_mask(LOG_GUEST_ERROR,
> > + "thread %d attempted to tlbunlock without having the
> > "
> > + "lock, tlb_lock state = %d\n",
> > + env->threadId, env->tlb_lock_state);
> > + g_assert(env->tlb_lock_state != HEX_LOCK_WAITING);
> > + return;
> > + }
> > +
> > + env->tlb_lock_count--;
> > + env->tlb_lock_state = HEX_LOCK_UNLOCKED;
> > + SET_SYSCFG_FIELD(env, SYSCFG_TLBLOCK, 0);
> > +
> > + /* Look for a thread to unlock */
> > + unsigned int this_threadId = env->threadId;
> > + CPUHexagonState *unlock_thread = NULL;
> > + CPUState *cs;
> > + CPU_FOREACH(cs) {
>
> Ditto.
>
> > + CPUHexagonState *thread = cpu_env(cs);
> > +
> > + /*
> > + * The hardware implements round-robin fairness, so we look for
> threads
> > + * starting at env->threadId + 1 and incrementing modulo the number
> of
> > + * threads.
> > + *
> > + * To implement this, we check if thread is a earlier in the modulo
> > + * sequence than unlock_thread.
> > + * if unlock thread is higher than this thread
> > + * thread must be between this thread and unlock_thread
> > + * else
> > + * thread higher than this thread is ahead of unlock_thread
> > + * thread must be lower then unlock thread
> > + */
> > + if (thread->tlb_lock_state == HEX_LOCK_WAITING) {
> > + if (!unlock_thread) {
> > + unlock_thread = thread;
> > + } else if (unlock_thread->threadId > this_threadId) {
> > + if (this_threadId < thread->threadId &&
> > + thread->threadId < unlock_thread->threadId) {
> > + unlock_thread = thread;
> > + }
> > + } else {
> > + if (thread->threadId > this_threadId) {
> > + unlock_thread = thread;
> > + }
> > + if (thread->threadId < unlock_thread->threadId) {
> > + unlock_thread = thread;
> > + }
> > + }
> > + }
> > + }
