In the process of decoupling KVM's view of the FGT bits from the
wider architectural state, use KVM's own FGT tables to build
a synthetic view of what is actually known.
This allows for some checking along the way.
Reviewed-by: Joey Gouly <joey.gouly@xxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
arch/arm64/include/asm/kvm_host.h | 14 ++++
arch/arm64/kvm/emulate-nested.c | 106 ++++++++++++++++++++++++++++++
2 files changed, 120 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 7a1ef5be7efb2..95fedd27f4bb8 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -607,6 +607,20 @@ struct kvm_sysreg_masks {
} mask[NR_SYS_REGS - __SANITISED_REG_START__];
};
+struct fgt_masks {
+ const char *str;
+ u64 mask;
+ u64 nmask;
+ u64 res0;
+};
+
+extern struct fgt_masks hfgrtr_masks;
+extern struct fgt_masks hfgwtr_masks;
+extern struct fgt_masks hfgitr_masks;
+extern struct fgt_masks hdfgrtr_masks;
+extern struct fgt_masks hdfgwtr_masks;
+extern struct fgt_masks hafgrtr_masks;
+
struct kvm_cpu_context {
struct user_pt_regs regs; /* sp = sp_el0 */
diff --git a/arch/arm64/kvm/emulate-nested.c b/arch/arm64/kvm/emulate-nested.c
index 52a2d63a667c9..528b33fcfcfd6 100644
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -2033,6 +2033,105 @@ static u32 encoding_next(u32 encoding)
return sys_reg(op0 + 1, 0, 0, 0, 0);
}
+#define FGT_MASKS(__n, __m) \
+ struct fgt_masks __n = { .str = #__m, .res0 = __m, }
+
+FGT_MASKS(hfgrtr_masks, HFGRTR_EL2_RES0);
+FGT_MASKS(hfgwtr_masks, HFGWTR_EL2_RES0);
+FGT_MASKS(hfgitr_masks, HFGITR_EL2_RES0);
+FGT_MASKS(hdfgrtr_masks, HDFGRTR_EL2_RES0);
+FGT_MASKS(hdfgwtr_masks, HDFGWTR_EL2_RES0);
+FGT_MASKS(hafgrtr_masks, HAFGRTR_EL2_RES0);
+
+static __init bool aggregate_fgt(union trap_config tc)
+{
+ struct fgt_masks *rmasks, *wmasks;
+
+ switch (tc.fgt) {
+ case HFGRTR_GROUP:
+ rmasks = &hfgrtr_masks;
+ wmasks = &hfgwtr_masks;
+ break;
+ case HDFGRTR_GROUP:
+ rmasks = &hdfgrtr_masks;
+ wmasks = &hdfgwtr_masks;
+ break;
+ case HAFGRTR_GROUP:
+ rmasks = &hafgrtr_masks;
+ wmasks = NULL;
+ break;
+ case HFGITR_GROUP:
+ rmasks = &hfgitr_masks;
+ wmasks = NULL;
+ break;
+ }
+
+ /*
+ * A bit can be reserved in either the R or W register, but
+ * not both.
+ */
+ if ((BIT(tc.bit) & rmasks->res0) &&
+ (!wmasks || (BIT(tc.bit) & wmasks->res0)))
+ return false;
+
+ if (tc.pol)
+ rmasks->mask |= BIT(tc.bit) & ~rmasks->res0;
+ else
+ rmasks->nmask |= BIT(tc.bit) & ~rmasks->res0;
+
+ if (wmasks) {
+ if (tc.pol)
+ wmasks->mask |= BIT(tc.bit) & ~wmasks->res0;
+ else
+ wmasks->nmask |= BIT(tc.bit) & ~wmasks->res0;
+ }
+
+ return true;
+}
+
+static __init int check_fgt_masks(struct fgt_masks *masks)
+{
+ unsigned long duplicate = masks->mask & masks->nmask;
+ u64 res0 = masks->res0;
+ int ret = 0;
+
+ if (duplicate) {
+ int i;
+
+ for_each_set_bit(i, &duplicate, 64) {
+ kvm_err("%s[%d] bit has both polarities\n",
+ masks->str, i);
+ }
+
+ ret = -EINVAL;
+ }
+
+ masks->res0 = ~(masks->mask | masks->nmask);
+ if (masks->res0 != res0)
+ kvm_info("Implicit %s = %016llx, expecting %016llx\n",
+ masks->str, masks->res0, res0);
+
+ return ret;
+}
+
+static __init int check_all_fgt_masks(int ret)
+{
+ static struct fgt_masks * const masks[] __initconst = {
+ &hfgrtr_masks,
+ &hfgwtr_masks,
+ &hfgitr_masks,
+ &hdfgrtr_masks,
+ &hdfgwtr_masks,
+ &hafgrtr_masks,
+ };
+ int err = 0;
+
+ for (int i = 0; i < ARRAY_SIZE(masks); i++)
+ err |= check_fgt_masks(masks[i]);
+
+ return ret ?: err;
+}
+
int __init populate_nv_trap_config(void)
{
int ret = 0;
@@ -2097,8 +2196,15 @@ int __init populate_nv_trap_config(void)
ret = xa_err(prev);
print_nv_trap_error(fgt, "Failed FGT insertion", ret);
}
+
+ if (!aggregate_fgt(tc)) {
+ ret = -EINVAL;
+ print_nv_trap_error(fgt, "FGT bit is reserved", ret);
+ }
}
+ ret = check_all_fgt_masks(ret);
+
kvm_info("nv: %ld fine grained trap handlers\n",
ARRAY_SIZE(encoding_to_fgt));
--
2.39.2
