[kvmtool PATCH v2 09/10] riscv: Add cpu-type command-line option

[Anup Patel <apatel@ventanamicro.com>]

Currently, the KVMTOOL always creates a VM with all available
ISA extensions virtualized by the in-kernel KVM module.

For better flexibility, add cpu-type command-line option using
which users can select one of the available CPU types for VM.

There are two CPU types supported at the moment namely "min"
and "max". The "min" CPU type implies VCPU with rv[64|32]imafdc
ISA whereas the "max" CPU type implies VCPU with all available
ISA extensions.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
 riscv/aia.c                         |  2 +-
 riscv/fdt.c                         | 68 +++++++++++++++++++++++++----
 riscv/include/kvm/kvm-arch.h        |  2 +
 riscv/include/kvm/kvm-config-arch.h | 10 +++++
 4 files changed, 73 insertions(+), 9 deletions(-)

diff --git a/riscv/aia.c b/riscv/aia.c
index 21d9704..cad53d4 100644
--- a/riscv/aia.c
+++ b/riscv/aia.c
@@ -209,7 +209,7 @@ void aia__create(struct kvm *kvm)
 		.flags = 0,
 	};
 
-	if (kvm->cfg.arch.ext_disabled[KVM_RISCV_ISA_EXT_SSAIA])
+	if (riscv__isa_extension_disabled(kvm, KVM_RISCV_ISA_EXT_SSAIA))
 		return;
 
 	err = ioctl(kvm->vm_fd, KVM_CREATE_DEVICE, &aia_device);
diff --git a/riscv/fdt.c b/riscv/fdt.c
index c741fd8..5d9b9bf 100644
--- a/riscv/fdt.c
+++ b/riscv/fdt.c
@@ -13,16 +13,17 @@ struct isa_ext_info {
 	const char *name;
 	unsigned long ext_id;
 	bool single_letter;
+	bool min_enabled;
 };
 
 struct isa_ext_info isa_info_arr[] = {
 	/* single-letter ordered canonically as "IEMAFDQCLBJTPVNSUHKORWXYZG" */
-	{"i",		KVM_RISCV_ISA_EXT_I,	.single_letter = true},
-	{"m",		KVM_RISCV_ISA_EXT_M,	.single_letter = true},
-	{"a",		KVM_RISCV_ISA_EXT_A,	.single_letter = true},
-	{"f",		KVM_RISCV_ISA_EXT_F,	.single_letter = true},
-	{"d",		KVM_RISCV_ISA_EXT_D,	.single_letter = true},
-	{"c",		KVM_RISCV_ISA_EXT_C,	.single_letter = true},
+	{"i",		KVM_RISCV_ISA_EXT_I,	.single_letter = true, .min_enabled = true},
+	{"m",		KVM_RISCV_ISA_EXT_M,	.single_letter = true, .min_enabled = true},
+	{"a",		KVM_RISCV_ISA_EXT_A,	.single_letter = true, .min_enabled = true},
+	{"f",		KVM_RISCV_ISA_EXT_F,	.single_letter = true, .min_enabled = true},
+	{"d",		KVM_RISCV_ISA_EXT_D,	.single_letter = true, .min_enabled = true},
+	{"c",		KVM_RISCV_ISA_EXT_C,	.single_letter = true, .min_enabled = true},
 	{"v",		KVM_RISCV_ISA_EXT_V,	.single_letter = true},
 	{"h",		KVM_RISCV_ISA_EXT_H,	.single_letter = true},
 	/* multi-letter sorted alphabetically */
@@ -89,6 +90,56 @@ struct isa_ext_info isa_info_arr[] = {
 	{"zvkt",	KVM_RISCV_ISA_EXT_ZVKT},
 };
 
+static bool __isa_ext_disabled(struct kvm *kvm, struct isa_ext_info *info)
+{
+	if (kvm->cfg.arch.cpu_type == RISCV__CPU_TYPE_MIN &&
+	    !info->min_enabled)
+		return true;
+
+	return kvm->cfg.arch.ext_disabled[info->ext_id];
+}
+
+static bool __isa_ext_warn_disable_failure(struct kvm *kvm, struct isa_ext_info *info)
+{
+	if (kvm->cfg.arch.cpu_type == RISCV__CPU_TYPE_MIN &&
+	    !info->min_enabled)
+		return false;
+
+	return true;
+}
+
+bool riscv__isa_extension_disabled(struct kvm *kvm, unsigned long isa_ext_id)
+{
+	struct isa_ext_info *info = NULL;
+	unsigned long i;
+
+	for (i = 0; i < ARRAY_SIZE(isa_info_arr); i++) {
+		if (isa_info_arr[i].ext_id == isa_ext_id) {
+			info = &isa_info_arr[i];
+		break;
+		}
+	}
+	if (!info)
+		return true;
+
+	return __isa_ext_disabled(kvm, info);
+}
+
+int riscv__cpu_type_parser(const struct option *opt, const char *arg, int unset)
+{
+	struct kvm *kvm = opt->ptr;
+
+	if ((strncmp(arg, "min", 3) && strncmp(arg, "max", 3)) || strlen(arg) != 3)
+		die("Invalid CPU type %s\n", arg);
+
+	if (!strcmp(arg, "max"))
+		kvm->cfg.arch.cpu_type = RISCV__CPU_TYPE_MAX;
+	else
+		kvm->cfg.arch.cpu_type = RISCV__CPU_TYPE_MIN;
+
+	return 0;
+}
+
 static void dump_fdt(const char *dtb_file, void *fdt)
 {
 	int count, fd;
@@ -139,9 +190,10 @@ static void generate_cpu_nodes(void *fdt, struct kvm *kvm)
 				/* This extension is not available in hardware */
 				continue;
 
-			if (kvm->cfg.arch.ext_disabled[isa_info_arr[i].ext_id]) {
+			if (__isa_ext_disabled(kvm, &isa_info_arr[i])) {
 				isa_ext_out = 0;
-				if (ioctl(vcpu->vcpu_fd, KVM_SET_ONE_REG, &reg) < 0)
+				if (ioctl(vcpu->vcpu_fd, KVM_SET_ONE_REG, &reg) < 0 &&
+				    __isa_ext_warn_disable_failure(kvm, &isa_info_arr[i]))
 					pr_warning("Failed to disable %s ISA exension\n",
 						   isa_info_arr[i].name);
 				continue;
diff --git a/riscv/include/kvm/kvm-arch.h b/riscv/include/kvm/kvm-arch.h
index f0f469f..1bb2d32 100644
--- a/riscv/include/kvm/kvm-arch.h
+++ b/riscv/include/kvm/kvm-arch.h
@@ -90,6 +90,8 @@ enum irqchip_type {
 	IRQCHIP_AIA
 };
 
+bool riscv__isa_extension_disabled(struct kvm *kvm, unsigned long ext_id);
+
 extern enum irqchip_type riscv_irqchip;
 extern bool riscv_irqchip_inkernel;
 extern void (*riscv_irqchip_trigger)(struct kvm *kvm, int irq,
diff --git a/riscv/include/kvm/kvm-config-arch.h b/riscv/include/kvm/kvm-config-arch.h
index 7e54d8a..6d9a29a 100644
--- a/riscv/include/kvm/kvm-config-arch.h
+++ b/riscv/include/kvm/kvm-config-arch.h
@@ -3,7 +3,13 @@
 
 #include "kvm/parse-options.h"
 
+enum riscv__cpu_type {
+	RISCV__CPU_TYPE_MAX = 0,
+	RISCV__CPU_TYPE_MIN
+};
+
 struct kvm_config_arch {
+	enum riscv__cpu_type cpu_type;
 	const char	*dump_dtb_filename;
 	u64		suspend_seconds;
 	u64		custom_mvendorid;
@@ -13,8 +19,12 @@ struct kvm_config_arch {
 	bool		sbi_ext_disabled[KVM_RISCV_SBI_EXT_MAX];
 };
 
+int riscv__cpu_type_parser(const struct option *opt, const char *arg, int unset);
+
 #define OPT_ARCH_RUN(pfx, cfg)						\
 	pfx,								\
+	OPT_CALLBACK('\0', "cpu-type", NULL, "min or max",		\
+		     "Choose the cpu type (default is max).", riscv__cpu_type_parser, kvm),\
 	OPT_STRING('\0', "dump-dtb", &(cfg)->dump_dtb_filename,		\
 		   ".dtb file", "Dump generated .dtb to specified file"),\
 	OPT_U64('\0', "suspend-seconds",				\
-- 
2.43.0