On 11/8/24 5:52 AM, Fea.Wang wrote:
Follow the Svukte spec, do the memory access address checking
1. Include instruction fetches or explicit memory accesses
2. System run in effective privilege U or VU
3. Check senvcfg[UKTE] being set, or hstatus[HUKTE] being set if
instruction is HLV, HLVX, HSV and excute from U mode to VU mode
typo: s/excute/execute
4. Depend on Sv39 and check virtual addresses bit[SXLEN-1]
5. Raises a page-fault exception corresponding to the original access
type.
Ref: https://github.com/riscv/riscv-isa-manual/pull/1564/files
Signed-off-by: Frank Chang <frank.ch...@sifive.com>
Signed-off-by: Fea.Wang <fea.w...@sifive.com>
Reviewed-by: Jim Shu <jim....@sifive.com>
---
target/riscv/cpu_helper.c | 57 +++++++++++++++++++++++++++++++++++++++
1 file changed, 57 insertions(+)
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 0a3ead69ea..725c049f7a 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -857,6 +857,57 @@ static int get_physical_address_pmp(CPURISCVState *env,
int *prot, hwaddr addr,
return TRANSLATE_SUCCESS;
}
+/*
+ * Return 'true' means no need to do svukte check, or need to do svukte and the
+ * address is valid. Return 'false' means need to do svukte check but address
+ * is invalid.
+ */
I think this function is doing a bit too much while not doing everything we
need.
For instance, we're still doing some checks in get_physical_address() prior to
calling it.
I would put all the svukte logic in two functions:
- 'do_svukte_check' would check all dependencies for the svukte check per se
- 'check_svukte_addr' would do the addr check if we need to do a svukte check
An example:
/* Returns 'true' if a svukte address check is needed */
static bool do_svukte_check(CPURISCVState *env, bool first_stage,
int mode, bool virt)
{
bool ukte;
/* Svukte extension depends on Sv39. */
if (!(env_archcpu(env)->cfg.ext_svukte &&
first_stage &&
VM_1_10_SV39 == get_field(env->satp, SATP64_MODE))) {
return false;
}
/*
* Check hstatus.HUKTE if the effective mode is switched to VU-mode by
* executing HLV/HLVX/HSV in U-mode.
* For other cases, check senvcfg.UKTE.
*/
if (env->priv == PRV_U && !env->virt_enabled && virt) {
ukte = !!(env->hstatus & HSTATUS_HUKTE);
} else {
ukte = !!(env->senvcfg & SENVCFG_UKTE);
}
if (!ukte) {
return false;
}
/*
* Svukte extension is qualified only in U or VU-mode.
*
* Effective mode can be switched to U or VU-mode by:
* - M-mode + mstatus.MPRV=1 + mstatus.MPP=U-mode.
* - Execute HLV/HLVX/HSV from HS-mode + hstatus.SPVP=0.
* - U-mode.
* - VU-mode.
* - Execute HLV/HLVX/HSV from U-mode + hstatus.HU=1.
*/
if (mode != PRV_U) {
return false;
}
return true;
}
static bool check_svukte_addr(CPURISCVState *env, vaddr addr)
{
uint32_t sxl = riscv_cpu_sxl(env);
sxl = (sxl == 0) ? MXL_RV32 : sxl;
uint32_t sxlen = 32 * sxl;
uint64_t high_bit = addr & (1UL << (sxlen - 1));
return !high_bit;
}
And then on get_physical_addr():
if (do_svukte_check(env, first_stage, mode, virt) &&
!check_svukte_addr(env, addr)) {
return TRANSLATE_FAIL;
}
Feel free to use these functions (compiled tested only) if you want. Thanks,
Daniel
+static bool check_svukte_valid(CPURISCVState *env, vaddr addr,
+ int mode, bool virt)
+{
+ /*
+ * Check hstatus.HUKTE if the effective mode is switched to VU-mode by
+ * executing HLV/HLVX/HSV in U-mode.
+ * For other cases, check senvcfg.UKTE.
+ */
+ bool ukte;
+ if (env->priv == PRV_U && !env->virt_enabled && virt) {
+ ukte = !!(env->hstatus & HSTATUS_HUKTE);
+ } else {
+ ukte = !!(env->senvcfg & SENVCFG_UKTE);
+ }
+
+ if (VM_1_10_SV39 != get_field(env->satp, SATP64_MODE)) {
+ /* Svukte extension depends on Sv39. */
+ return true;
+ }> +
+ /*
+ * Svukte extension is qualified only in U or VU-mode.
+ *
+ * Effective mode can be switched to U or VU-mode by:
+ * - M-mode + mstatus.MPRV=1 + mstatus.MPP=U-mode.
+ * - Execute HLV/HLVX/HSV from HS-mode + hstatus.SPVP=0.
+ * - U-mode.
+ * - VU-mode.
+ * - Execute HLV/HLVX/HSV from U-mode + hstatus.HU=1.
+ */
+ if (mode != PRV_U) {
+ return true;
+ }
+
+ if (!ukte) {
+ return true;
+ }
+
+ uint32_t sxl = riscv_cpu_sxl(env);
+ sxl = (sxl == 0) ? MXL_RV32 : sxl;
+ uint32_t sxlen = 32 * sxl;
+ uint64_t high_bit = addr & (1UL << (sxlen - 1));
+
+ return !high_bit;
+}
+
/*
* get_physical_address - get the physical address for this virtual address
*
@@ -894,6 +945,7 @@ static int get_physical_address(CPURISCVState *env, hwaddr
*physical,
MemTxResult res;
MemTxAttrs attrs = MEMTXATTRS_UNSPECIFIED;
int mode = mmuidx_priv(mmu_idx);
+ bool virt = mmuidx_2stage(mmu_idx);
bool use_background = false;
hwaddr ppn;
int napot_bits = 0;
@@ -901,6 +953,11 @@ static int get_physical_address(CPURISCVState *env, hwaddr
*physical,
bool is_sstack_idx = ((mmu_idx & MMU_IDX_SS_WRITE) == MMU_IDX_SS_WRITE);
bool sstack_page = false;
+ if (env_archcpu(env)->cfg.ext_svukte && first_stage &&
+ !check_svukte_valid(env, addr, mode, virt)) {
+ return TRANSLATE_FAIL;
+ }
+
/*
* Check if we should use the background registers for the two
* stage translation. We don't need to check if we actually need
