KVM: arm64: Fix FEAT_SPE_FnE to use PMSIDR_EL1.FnE, not PMSVer

FEAT_SPE_FnE is architecturally detected via PMSIDR_EL1.FnE [6], not
ID_AA64DFR0_EL1.PMSVer. The FEAT_X macro form (register, field, value)
cannot encode a PMSIDR_EL1-based feature, so FEAT_SPE_FnE was defined
identically to FEAT_SPEv1p2 (ID_AA64DFR0_EL1, PMSVer, V1P2), producing
a duplicate that used PMSVer >= V1P2 as a proxy.

Replace the macro with feat_spe_fne(), following the same pattern as
the sibling feat_spe_fds(): guard on FEAT_SPEv1p2 and read
PMSIDR_EL1.FnE [6] directly. Wire the two NEEDS_FEAT consumers to use
the new function.

Remove the now-unused FEAT_SPE_FnE macro.

Fixes: 63d423a ("KVM: arm64: Switch to table-driven FGU configuration")
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://patch.msgid.link/20260424084908.370776-4-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org

Author: Fuad Tabba

arch/arm64/kvm/config.c

@@ -131,7 +131,6 @@ struct reg_feat_map_desc {
 	}
 
 #define FEAT_SPE		ID_AA64DFR0_EL1, PMSVer, IMP
-#define FEAT_SPE_FnE		ID_AA64DFR0_EL1, PMSVer, V1P2
 #define FEAT_BRBE		ID_AA64DFR0_EL1, BRBE, IMP
 #define FEAT_TRC_SR		ID_AA64DFR0_EL1, TraceVer, IMP
 #define FEAT_PMUv3		ID_AA64DFR0_EL1, PMUVer, IMP
@@ -302,6 +301,16 @@ static bool feat_spe_fds(struct kvm *kvm)
 		(read_sysreg_s(SYS_PMSIDR_EL1) & PMSIDR_EL1_FDS));
 }
 
+static bool feat_spe_fne(struct kvm *kvm)
+{
+	/*
+	 * Revisit this if KVM ever supports SPE -- this really should
+	 * look at the guest's view of PMSIDR_EL1.
+	 */
+	return (kvm_has_feat(kvm, FEAT_SPEv1p2) &&
+		(read_sysreg_s(SYS_PMSIDR_EL1) & PMSIDR_EL1_FnE));
+}
+
 static bool feat_trbe_mpam(struct kvm *kvm)
 {
 	/*
@@ -537,7 +546,7 @@ static const struct reg_bits_to_feat_map hdfgrtr_feat_map[] = {
 		   HDFGRTR_EL2_PMBPTR_EL1	|
 		   HDFGRTR_EL2_PMBLIMITR_EL1,
 		   FEAT_SPE),
-	NEEDS_FEAT(HDFGRTR_EL2_nPMSNEVFR_EL1, FEAT_SPE_FnE),
+	NEEDS_FEAT(HDFGRTR_EL2_nPMSNEVFR_EL1, feat_spe_fne),
 	NEEDS_FEAT(HDFGRTR_EL2_nBRBDATA		|
 		   HDFGRTR_EL2_nBRBCTL		|
 		   HDFGRTR_EL2_nBRBIDR,
@@ -605,7 +614,7 @@ static const struct reg_bits_to_feat_map hdfgwtr_feat_map[] = {
 		   HDFGWTR_EL2_PMBPTR_EL1	|
 		   HDFGWTR_EL2_PMBLIMITR_EL1,
 		   FEAT_SPE),
-	NEEDS_FEAT(HDFGWTR_EL2_nPMSNEVFR_EL1, FEAT_SPE_FnE),
+	NEEDS_FEAT(HDFGWTR_EL2_nPMSNEVFR_EL1, feat_spe_fne),
 	NEEDS_FEAT(HDFGWTR_EL2_nBRBDATA		|
 		   HDFGWTR_EL2_nBRBCTL,
 		   FEAT_BRBE),