KVM: arm64: selftests: Delete core_reg_fixup

core_reg_fixup() complicates sharing the get-reg-list test with
other architectures. Rather than work at keeping it, with plenty
of #ifdeffery, just delete it, as it's unlikely to test a kernel
based on anything older than v5.2 with the get-reg-list test,
which is a test meant to check for regressions in new kernels.
(And, an older version of the test can still be used for older
kernels if necessary.)

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Haibo Xu <haibo1.xu@intel.com>
Signed-off-by: Anup Patel <anup@brainfault.org>

Author: Andrew Jones

tools/testing/selftests/kvm/aarch64/get-reg-list.c

@@ -17,12 +17,10 @@
  * by running the test with the --list command line argument.
  *
  * Note, the blessed list should be created from the oldest possible
- * kernel. We can't go older than v4.15, though, because that's the first
- * release to expose the ID system registers in KVM_GET_REG_LIST, see
- * commit 93390c0a1b20 ("arm64: KVM: Hide unsupported AArch64 CPU features
- * from guests"). Also, one must use the --core-reg-fixup command line
- * option when running on an older kernel that doesn't include df205b5c6328
- * ("KVM: arm64: Filter out invalid core register IDs in KVM_GET_REG_LIST")
+ * kernel. We can't go older than v5.2, though, because that's the first
+ * release which includes df205b5c6328 ("KVM: arm64: Filter out invalid
+ * core register IDs in KVM_GET_REG_LIST"). Without that commit the core
+ * registers won't match expectations.
  */
 #include <stdio.h>
 #include <stdlib.h>
@@ -317,63 +315,6 @@ static void print_reg(const char *prefix, __u64 id)
 	}
 }
 
-/*
- * Older kernels listed each 32-bit word of CORE registers separately.
- * For 64 and 128-bit registers we need to ignore the extra words. We
- * also need to fixup the sizes, because the older kernels stated all
- * registers were 64-bit, even when they weren't.
- */
-static void core_reg_fixup(void)
-{
-	struct kvm_reg_list *tmp;
-	__u64 id, core_off;
-	int i;
-
-	tmp = calloc(1, sizeof(*tmp) + reg_list->n * sizeof(__u64));
-
-	for (i = 0; i < reg_list->n; ++i) {
-		id = reg_list->reg[i];
-
-		if ((id & KVM_REG_ARM_COPROC_MASK) != KVM_REG_ARM_CORE) {
-			tmp->reg[tmp->n++] = id;
-			continue;
-		}
-
-		core_off = id & ~REG_MASK;
-
-		switch (core_off) {
-		case 0x52: case 0xd2: case 0xd6:
-			/*
-			 * These offsets are pointing at padding.
-			 * We need to ignore them too.
-			 */
-			continue;
-		case KVM_REG_ARM_CORE_REG(fp_regs.vregs[0]) ...
-		     KVM_REG_ARM_CORE_REG(fp_regs.vregs[31]):
-			if (core_off & 3)
-				continue;
-			id &= ~KVM_REG_SIZE_MASK;
-			id |= KVM_REG_SIZE_U128;
-			tmp->reg[tmp->n++] = id;
-			continue;
-		case KVM_REG_ARM_CORE_REG(fp_regs.fpsr):
-		case KVM_REG_ARM_CORE_REG(fp_regs.fpcr):
-			id &= ~KVM_REG_SIZE_MASK;
-			id |= KVM_REG_SIZE_U32;
-			tmp->reg[tmp->n++] = id;
-			continue;
-		default:
-			if (core_off & 1)
-				continue;
-			tmp->reg[tmp->n++] = id;
-			break;
-		}
-	}
-
-	free(reg_list);
-	reg_list = tmp;
-}
-
 static void prepare_vcpu_init(struct vcpu_reg_list *c, struct kvm_vcpu_init *init)
 {
 	struct vcpu_reg_sublist *s;
@@ -412,7 +353,6 @@ static void check_supported(struct vcpu_reg_list *c)
 
 static bool print_list;
 static bool print_filtered;
-static bool fixup_core_regs;
 
 static void run_test(struct vcpu_reg_list *c)
 {
@@ -433,9 +373,6 @@ static void run_test(struct vcpu_reg_list *c)
 
 	reg_list = vcpu_get_reg_list(vcpu);
 
-	if (fixup_core_regs)
-		core_reg_fixup();
-
 	if (print_list || print_filtered) {
 		putchar('\n');
 		for_each_reg(i) {
@@ -563,7 +500,7 @@ static void help(void)
 
 	printf(
 	"\n"
-	"usage: get-reg-list [--config=<selection>] [--list] [--list-filtered] [--core-reg-fixup]\n\n"
+	"usage: get-reg-list [--config=<selection>] [--list] [--list-filtered]\n\n"
 	" --config=<selection>        Used to select a specific vcpu configuration for the test/listing\n"
 	"                             '<selection>' may be\n");
 
@@ -577,7 +514,6 @@ static void help(void)
 	"\n"
 	" --list                      Print the register list rather than test it (requires --config)\n"
 	" --list-filtered             Print registers that would normally be filtered out (requires --config)\n"
-	" --core-reg-fixup            Needed when running on old kernels with broken core reg listings\n"
 	"\n"
 	);
 }
@@ -609,9 +545,7 @@ int main(int ac, char **av)
 	pid_t pid;
 
 	for (i = 1; i < ac; ++i) {
-		if (strcmp(av[i], "--core-reg-fixup") == 0)
-			fixup_core_regs = true;
-		else if (strncmp(av[i], "--config", 8) == 0)
+		if (strncmp(av[i], "--config", 8) == 0)
 			sel = parse_config(av[i]);
 		else if (strcmp(av[i], "--list") == 0)
 			print_list = true;
@@ -654,8 +588,11 @@ int main(int ac, char **av)
 }
 
 /*
- * The current blessed list was primed with the output of kernel version
+ * The original blessed list was primed with the output of kernel version
  * v4.15 with --core-reg-fixup and then later updated with new registers.
+ * (The --core-reg-fixup option and it's fixup function have been removed
+ * from the test, as it's unlikely to use this type of test on a kernel
+ * older than v5.2.)
  *
  * The blessed list is up to date with kernel version v6.4 (or so we hope)
  */