[kvm-unit-tests PATCH 2/2] riscv: Add tests for SBI FWFT extension

["Clément Léger" <cleger@rivosinc.com>]

This commit add tests for a the FWFT SBI extension. Currently, only
the reserved range as well as the misaligned exception delegation.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
---
 riscv/Makefile      |   2 +-
 lib/riscv/asm/sbi.h |  31 +++++++++
 riscv/sbi-fwft.c    | 153 ++++++++++++++++++++++++++++++++++++++++++++
 riscv/sbi.c         |   3 +
 4 files changed, 188 insertions(+), 1 deletion(-)
 create mode 100644 riscv/sbi-fwft.c

diff --git a/riscv/Makefile b/riscv/Makefile
index 5b5e157c..52718f3f 100644
--- a/riscv/Makefile
+++ b/riscv/Makefile
@@ -17,7 +17,7 @@ tests += $(TEST_DIR)/sieve.$(exe)
 
 all: $(tests)
 
-$(TEST_DIR)/sbi-deps = $(TEST_DIR)/sbi-asm.o
+$(TEST_DIR)/sbi-deps = $(TEST_DIR)/sbi-asm.o $(TEST_DIR)/sbi-fwft.o
 
 # When built for EFI sieve needs extra memory, run with e.g. '-m 256' on QEMU
 $(TEST_DIR)/sieve.$(exe): AUXFLAGS = 0x1
diff --git a/lib/riscv/asm/sbi.h b/lib/riscv/asm/sbi.h
index 98a9b097..27e6fcdb 100644
--- a/lib/riscv/asm/sbi.h
+++ b/lib/riscv/asm/sbi.h
@@ -11,6 +11,9 @@
 #define SBI_ERR_ALREADY_AVAILABLE	-6
 #define SBI_ERR_ALREADY_STARTED		-7
 #define SBI_ERR_ALREADY_STOPPED		-8
+#define SBI_ERR_NO_SHMEM		-9
+#define SBI_ERR_INVALID_STATE		-10
+#define SBI_ERR_BAD_RANGE		-11
 
 #ifndef __ASSEMBLY__
 #include <cpumask.h>
@@ -23,6 +26,7 @@ enum sbi_ext_id {
 	SBI_EXT_SRST = 0x53525354,
 	SBI_EXT_DBCN = 0x4442434E,
 	SBI_EXT_SUSP = 0x53555350,
+	SBI_EXT_FWFT = 0x46574654,
 };
 
 enum sbi_ext_base_fid {
@@ -71,6 +75,33 @@ enum sbi_ext_dbcn_fid {
 	SBI_EXT_DBCN_CONSOLE_WRITE_BYTE,
 };
 
+/* SBI function IDs for FW feature extension */
+#define SBI_EXT_FWFT_SET		0x0
+#define SBI_EXT_FWFT_GET		0x1
+
+enum sbi_fwft_feature_t {
+	SBI_FWFT_MISALIGNED_EXC_DELEG		= 0x0,
+	SBI_FWFT_LANDING_PAD			= 0x1,
+	SBI_FWFT_SHADOW_STACK			= 0x2,
+	SBI_FWFT_DOUBLE_TRAP			= 0x3,
+	SBI_FWFT_PTE_AD_HARDWARE_UPDATE		= 0x4,
+	SBI_FWFT_POINTER_MASKING_PMLEN		= 0x5,
+	SBI_FWFT_LOCAL_RESERVED_START		= 0x6,
+	SBI_FWFT_LOCAL_RESERVED_END		= 0x3fffffff,
+	SBI_FWFT_LOCAL_PLATFORM_START		= 0x40000000,
+	SBI_FWFT_LOCAL_PLATFORM_END		= 0x7fffffff,
+
+	SBI_FWFT_GLOBAL_RESERVED_START		= 0x80000000,
+	SBI_FWFT_GLOBAL_RESERVED_END		= 0xbfffffff,
+	SBI_FWFT_GLOBAL_PLATFORM_START		= 0xc0000000,
+	SBI_FWFT_GLOBAL_PLATFORM_END		= 0xffffffff,
+};
+
+#define SBI_FWFT_PLATFORM_FEATURE_BIT		(1 << 30)
+#define SBI_FWFT_GLOBAL_FEATURE_BIT		(1 << 31)
+
+#define SBI_FWFT_SET_FLAG_LOCK			(1 << 0)
+
 struct sbiret {
 	long error;
 	long value;
diff --git a/riscv/sbi-fwft.c b/riscv/sbi-fwft.c
new file mode 100644
index 00000000..8a7f2070
--- /dev/null
+++ b/riscv/sbi-fwft.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SBI verification
+ *
+ * Copyright (C) 2024, Rivos Inc., Clément Léger <cleger@rivosinc.com>
+ */
+#include <libcflat.h>
+#include <stdlib.h>
+
+#include <asm/csr.h>
+#include <asm/processor.h>
+#include <asm/ptrace.h>
+#include <asm/sbi.h>
+
+void check_fwft(void);
+
+static int fwft_set(unsigned long feature_id, unsigned long value,
+		       unsigned long flags)
+{
+	struct sbiret ret = sbi_ecall(SBI_EXT_FWFT, SBI_EXT_FWFT_SET,
+				      feature_id, value, flags, 0, 0, 0);
+
+	return ret.error;
+}
+
+static int fwft_get(unsigned long feature_id, unsigned long *value)
+{
+	struct sbiret ret = sbi_ecall(SBI_EXT_FWFT, SBI_EXT_FWFT_GET,
+				      feature_id, 0, 0, 0, 0, 0);
+
+	*value = ret.value;
+
+	return ret.error;
+}
+
+static void fwft_check_reserved(unsigned long id)
+{
+	int ret;
+	bool pass = true;
+	unsigned long value;
+
+	ret = fwft_get(id, &value);
+	if (ret != SBI_ERR_DENIED)
+		pass = false;
+
+	ret = fwft_set(id, 1, 0);
+	if (ret != SBI_ERR_DENIED)
+		pass = false;
+
+	report(pass, "get/set reserved feature 0x%lx error == SBI_ERR_DENIED", id);
+}
+
+static void fwft_check_denied(void)
+{
+	fwft_check_reserved(SBI_FWFT_LOCAL_RESERVED_START);
+	fwft_check_reserved(SBI_FWFT_LOCAL_RESERVED_END);
+	fwft_check_reserved(SBI_FWFT_GLOBAL_RESERVED_START);
+	fwft_check_reserved(SBI_FWFT_GLOBAL_RESERVED_END);
+}
+
+static bool misaligned_handled;
+
+static void misaligned_handler(struct pt_regs *regs)
+{
+	misaligned_handled = true;
+	regs->epc += 4;
+}
+
+static void fwft_check_misaligned(void)
+{
+	int ret;
+	unsigned long value;
+
+	report_prefix_push("misaligned_deleg");
+
+	ret = fwft_get(SBI_FWFT_MISALIGNED_EXC_DELEG, &value);
+	if (ret == SBI_ERR_NOT_SUPPORTED) {
+		report_skip("SBI_FWFT_MISALIGNED_EXC_DELEG is not supported");
+		return;
+	}
+	report(!ret, "Get misaligned deleg feature no error");
+	if (ret)
+		return;
+
+	ret = fwft_set(SBI_FWFT_MISALIGNED_EXC_DELEG, 2, 0);
+	report(ret == SBI_ERR_INVALID_PARAM, "Set misaligned deleg feature invalid value error");
+	ret = fwft_set(SBI_FWFT_MISALIGNED_EXC_DELEG, 0xFFFFFFFF, 0);
+	report(ret == SBI_ERR_INVALID_PARAM, "Set misaligned deleg feature invalid value error");
+
+	/* Set to 0 and check after with get */
+	ret = fwft_set(SBI_FWFT_MISALIGNED_EXC_DELEG, 0, 0);
+	report(!ret, "Set misaligned deleg feature value no error");
+	ret = fwft_get(SBI_FWFT_MISALIGNED_EXC_DELEG, &value);
+	if (ret)
+		report_fail("Get misaligned deleg feature after set");
+	else
+		report(value == 0, "Set misaligned deleg feature value 0");
+
+	/* Set to 1 and check after with get */
+	ret = fwft_set(SBI_FWFT_MISALIGNED_EXC_DELEG, 1, 0);
+	report(!ret, "Set misaligned deleg feature value no error");
+	ret = fwft_get(SBI_FWFT_MISALIGNED_EXC_DELEG, &value);
+	if (ret)
+		report_fail("Get misaligned deleg feature after set");
+	else
+		report(value == 1, "Set misaligned deleg feature value 1");
+
+	install_exception_handler(EXC_LOAD_MISALIGNED, misaligned_handler);
+
+	asm volatile (
+		".option norvc\n"
+		"lw %[val], 1(%[val_addr])"
+		: [val] "+r" (value)
+		: [val_addr] "r" (&value)
+		: "memory");
+
+	if (!misaligned_handled)
+		report_skip("Verify misaligned load exception trap in supervisor");
+	else
+		report_pass("Verify misaligned load exception trap in supervisor");
+
+	install_exception_handler(EXC_LOAD_MISALIGNED, NULL);
+
+	report_prefix_pop();
+}
+
+void check_fwft(void)
+{
+	struct sbiret ret;
+
+	report_prefix_push("fwft");
+
+	if (!sbi_probe(SBI_EXT_FWFT)) {
+		report_skip("FWFT extension not available");
+		report_prefix_pop();
+		return;
+	}
+
+	ret = sbi_ecall(SBI_EXT_BASE, SBI_EXT_BASE_PROBE_EXT, SBI_EXT_FWFT, 0, 0, 0, 0, 0);
+	report(!ret.error, "FWFT extension probing no error");
+	if (ret.error)
+		goto done;
+
+	if (ret.value == 0) {
+		report_skip("FWFT extension is not present");
+		goto done;
+	}
+
+	fwft_check_denied();
+	fwft_check_misaligned();
+done:
+	report_prefix_pop();
+}
diff --git a/riscv/sbi.c b/riscv/sbi.c
index 6f4ddaf1..8600e38e 100644
--- a/riscv/sbi.c
+++ b/riscv/sbi.c
@@ -32,6 +32,8 @@
 
 #define	HIGH_ADDR_BOUNDARY	((phys_addr_t)1 << 32)
 
+void check_fwft(void);
+
 static long __labs(long a)
 {
 	return __builtin_labs(a);
@@ -1451,6 +1453,7 @@ int main(int argc, char **argv)
 	check_hsm();
 	check_dbcn();
 	check_susp();
+	check_fwft();
 
 	return report_summary();
 }
-- 
2.47.1


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