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Fix Svukte implementation #2171

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Merged
aswaterman merged 1 commit into from
Dec 2, 2025
Merged

Fix Svukte implementation #2171

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35 changes: 21 additions & 14 deletions riscv/mmu.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -630,28 +630,35 @@ reg_t mmu_t::s2xlate(reg_t gva, reg_t gpa, access_type type, access_type trap_ty
}
}

bool mmu_t::check_svukte_qualified(reg_t addr, reg_t mode, bool forced_virt)
bool mmu_t::svukte_qualified(mem_access_info_t access_info)
{
state_t* state = proc->get_state();

if (mode != PRV_U)
return true;
if (access_info.effective_priv != PRV_U)
return false;

if (proc->extension_enabled('S') && get_field(state->senvcfg->read(), SENVCFG_UKTE)) {
if (forced_virt && state->prv == PRV_U) {
bool hstatus_hukte = proc->extension_enabled('H') && (get_field(state->hstatus->read(), HSTATUS_HUKTE) == 1);
return !hstatus_hukte;
}
bool ukte = get_field(state->senvcfg->read(), SENVCFG_UKTE);
if (access_info.flags.forced_virt && state->prv == PRV_U)
ukte = get_field(state->hstatus->read(), HSTATUS_HUKTE);

assert(proc->get_xlen() == 64);
if ((addr >> 63) & 1) {
return (state->v || forced_virt) && ((state->vsatp->read() & SATP64_MODE) == 0);
}
}
if (!ukte)
return false;

reg_t mode_mask = proc->get_xlen() == 32 ? SATP32_MODE : SATP64_MODE;
if (get_field(proc->get_state()->satp->readvirt(access_info.effective_virt), mode_mask) == 0)
return false;

return true;
}

bool mmu_t::svukte_fault(reg_t addr, mem_access_info_t access_info)
{
if (!svukte_qualified(access_info))
return false;

return addr >> (proc->get_xlen() - 1);
}

reg_t mmu_t::walk(mem_access_info_t access_info)
{
access_type type = access_info.type;
Expand All @@ -674,7 +681,7 @@ reg_t mmu_t::walk(mem_access_info_t access_info)
if (vm.levels == 0)
return s2xlate(addr, addr & ((reg_t(2) << (proc->xlen-1))-1), type, type, virt, hlvx, false) & ~page_mask; // zero-extend from xlen

if (proc->extension_enabled(EXT_SVUKTE) && !check_svukte_qualified(addr, mode, access_info.flags.forced_virt)) {
if (svukte_fault(addr, access_info)) {
throw_page_fault_exception(virt, addr, type);
}

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3 changes: 2 additions & 1 deletion riscv/mmu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -453,7 +453,8 @@ class mmu_t
check_triggers(operation, address, virt, address, data);
}
void check_triggers(triggers::operation_t operation, reg_t address, bool virt, reg_t tval, std::optional<reg_t> data);
bool check_svukte_qualified(reg_t addr, reg_t mode, bool forced_virt);
bool svukte_qualified(mem_access_info_t access_info);
bool svukte_fault(reg_t addr, mem_access_info_t access_info);
reg_t translate(mem_access_info_t access_info, reg_t len);

reg_t pte_load(reg_t pte_paddr, reg_t addr, bool virt, access_type trap_type, size_t ptesize) {
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