On 16/12/2023 14.42, Nicholas Piggin wrote:

Why don't you use the definitions from ppc_asm.h above?

+static bool cpu_has_heir(void)
+{
+	uint32_t pvr = mfspr(287);	/* Processor Version Register */
+
+	if (!machine_is_powernv())
+		return false;
+
+	/* POWER6 has HEIR, but QEMU powernv support does not go that far */
+	switch (pvr >> 16) {
+	case 0x4b:			/* POWER8E */
+	case 0x4c:			/* POWER8NVL */
+	case 0x4d:			/* POWER8 */
+	case 0x4e:			/* POWER9 */
+	case 0x80:			/* POWER10 */

I'd suggest to introduce some #defines for those PVR values instead of using 
magic numbers all over the place?

+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool cpu_has_prefix(void)
+{
+	uint32_t pvr = mfspr(287);	/* Processor Version Register */
+	switch (pvr >> 16) {
+	case 0x80:			/* POWER10 */
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool cpu_has_lev_in_srr1(void)
+{
+	uint32_t pvr = mfspr(287);	/* Processor Version Register */
+	switch (pvr >> 16) {
+	case 0x80:			/* POWER10 */
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool regs_is_prefix(volatile struct pt_regs *regs)
+{
+	return (regs->msr >> (63-34)) & 1;

You introduced a bunch of new #define MSR_xx statements ... why not for this 
one, too?

+}
+
+static void regs_advance_insn(struct pt_regs *regs)
+{
+	if (regs_is_prefix(regs))
+		regs->nip += 8;
+	else
+		regs->nip += 4;
+}
+
+static volatile bool got_interrupt;
+static volatile struct pt_regs recorded_regs;
+
+static void mce_handler(struct pt_regs *regs, void *opaque)
+{
+	got_interrupt = true;
+	memcpy((void *)&recorded_regs, regs, sizeof(struct pt_regs));
+	regs_advance_insn(regs);
+}
+
+static void test_mce(void)
+{
+	unsigned long addr = -4ULL;
+	uint8_t tmp;
+
+	handle_exception(0x200, mce_handler, NULL);
+
+	if (machine_is_powernv()) {
+		enable_mcheck();
+	} else {
+		report(mfmsr() & MSR_ME, "pseries machine has MSR[ME]=1");
+		if (!(mfmsr() & MSR_ME)) { /* try to fix it */
+			enable_mcheck();
+		}
+		if (mfmsr() & MSR_ME) {
+			disable_mcheck();
+			report(mfmsr() & MSR_ME, "pseries is unable to change MSR[ME]");
+			if (!(mfmsr() & MSR_ME)) { /* try to fix it */
+				enable_mcheck();
+			}
+		}
+	}
+
+	asm volatile("lbz %0,0(%1)" : "=r"(tmp) : "r"(addr));
+
+	report(got_interrupt, "MCE on access to invalid real address");
+	report(mfspr(SPR_DAR) == addr, "MCE sets DAR correctly");
+	got_interrupt = false;
+}
+
+static void dseg_handler(struct pt_regs *regs, void *data)
+{
+	got_interrupt = true;
+	memcpy((void *)&recorded_regs, regs, sizeof(struct pt_regs));
+	regs_advance_insn(regs);
+	regs->msr &= ~MSR_DR;
+}
+
+static void test_dseg(void)
+{
+	uint64_t msr, tmp;
+
+	report_prefix_push("data segment");
+
+	/* Some HV start in radix mode and need 0x300 */
+	handle_exception(0x300, &dseg_handler, NULL);
+	handle_exception(0x380, &dseg_handler, NULL);
+
+	asm volatile(
+"		mfmsr	%0		\n \
+		ori	%0,%0,%2	\n \
+		mtmsrd	%0		\n \
+		lbz	%1,0(0)		"
+		: "=r"(msr), "=r"(tmp) : "i"(MSR_DR): "memory");
+
+	report(got_interrupt, "interrupt on NULL dereference");
+	got_interrupt = false;
+
+	handle_exception(0x300, NULL, NULL);
+	handle_exception(0x380, NULL, NULL);
+
+	report_prefix_pop();
+}
+
+static void dec_handler(struct pt_regs *regs, void *data)
+{
+	got_interrupt = true;
+	memcpy((void *)&recorded_regs, regs, sizeof(struct pt_regs));
+	regs->msr &= ~MSR_EE;
+}
+
+static void test_dec(void)
+{
+	uint64_t msr;
+
+	report_prefix_push("decrementer");
+
+	handle_exception(0x900, &dec_handler, NULL);
+
+	asm volatile(
+"		mtdec	%1		\n \
+		mfmsr	%0		\n \
+		ori	%0,%0,%2	\n \
+		mtmsrd	%0,1		"
+		: "=r"(msr) : "r"(10000), "i"(MSR_EE): "memory");
+
+	while (!got_interrupt)
+		;

Maybe add a timeout (in case the interrupt never fires)?

+	report(got_interrupt, "interrupt on decrementer underflow");
+	got_interrupt = false;
+
+	handle_exception(0x900, NULL, NULL);
+
+	if (!machine_is_powernv())
+		goto done;
+
+	handle_exception(0x980, &dec_handler, NULL);
+
+	mtspr(SPR_LPCR, mfspr(SPR_LPCR) | LPCR_HDICE);
+	asm volatile(
+"		mtspr	0x136,%1	\n \
+		mtdec	%3		\n \
+		mfmsr	%0		\n \
+		ori	%0,%0,%2	\n \
+		mtmsrd	%0,1		"
+		: "=r"(msr) : "r"(10000), "i"(MSR_EE), "r"(0x7fffffff): "memory");
+
+	while (!got_interrupt)
+		;

dito?

+	mtspr(SPR_LPCR, mfspr(SPR_LPCR) & ~LPCR_HDICE);
+
+	report(got_interrupt, "interrupt on hdecrementer underflow");
+	got_interrupt = false;
+
+	handle_exception(0x980, NULL, NULL);
+
+done:
+	report_prefix_pop();
+}

  Thomas