[PATCH v2 03/10] KVM: arm64: Enforce absence of FEAT_FGT on FGT registers
Marc Zyngier
maz at kernel.org
Thu Sep 18 08:13:55 PDT 2025
As we want to enforce FGT registers behaving as RES0 when FEAT_FGT
is not exposed to the guest, We move a bumch of things that are
so far passed as parameter into a structure that points to the
bit description.
Signed-off-by: Marc Zyngier <maz at kernel.org>
---
arch/arm64/kvm/config.c | 126 ++++++++++++++++++++++++----------------
1 file changed, 77 insertions(+), 49 deletions(-)
diff --git a/arch/arm64/kvm/config.c b/arch/arm64/kvm/config.c
index c2bfffe660bca..bb38364d55e9a 100644
--- a/arch/arm64/kvm/config.c
+++ b/arch/arm64/kvm/config.c
@@ -458,6 +458,10 @@ static const struct reg_bits_to_feat_map hfgrtr_feat_map[] = {
NEVER_FGU, FEAT_AA64EL1),
};
+
+static const DECLARE_FEAT_MAP_FGT(hfgrtr_desc, hfgrtr_masks,
+ hfgrtr_feat_map, FEAT_FGT);
+
static const struct reg_bits_to_feat_map hfgwtr_feat_map[] = {
NEEDS_FEAT(HFGWTR_EL2_nAMAIR2_EL1 |
HFGWTR_EL2_nMAIR2_EL1,
@@ -522,6 +526,9 @@ static const struct reg_bits_to_feat_map hfgwtr_feat_map[] = {
NEVER_FGU, FEAT_AA64EL1),
};
+static const DECLARE_FEAT_MAP_FGT(hfgwtr_desc, hfgwtr_masks,
+ hfgwtr_feat_map, FEAT_FGT);
+
static const struct reg_bits_to_feat_map hdfgrtr_feat_map[] = {
NEEDS_FEAT(HDFGRTR_EL2_PMBIDR_EL1 |
HDFGRTR_EL2_PMSLATFR_EL1 |
@@ -589,6 +596,9 @@ static const struct reg_bits_to_feat_map hdfgrtr_feat_map[] = {
NEVER_FGU, FEAT_AA64EL1)
};
+static const DECLARE_FEAT_MAP_FGT(hdfgrtr_desc, hdfgrtr_masks,
+ hdfgrtr_feat_map, FEAT_FGT);
+
static const struct reg_bits_to_feat_map hdfgwtr_feat_map[] = {
NEEDS_FEAT(HDFGWTR_EL2_PMSLATFR_EL1 |
HDFGWTR_EL2_PMSIRR_EL1 |
@@ -649,6 +659,8 @@ static const struct reg_bits_to_feat_map hdfgwtr_feat_map[] = {
NEEDS_FEAT(HDFGWTR_EL2_TRFCR_EL1, FEAT_TRF),
};
+static const DECLARE_FEAT_MAP_FGT(hdfgwtr_desc, hdfgwtr_masks,
+ hdfgwtr_feat_map, FEAT_FGT);
static const struct reg_bits_to_feat_map hfgitr_feat_map[] = {
NEEDS_FEAT(HFGITR_EL2_PSBCSYNC, FEAT_SPEv1p5),
@@ -723,6 +735,9 @@ static const struct reg_bits_to_feat_map hfgitr_feat_map[] = {
NEVER_FGU, FEAT_AA64EL1),
};
+static const DECLARE_FEAT_MAP_FGT(hfgitr_desc, hfgitr_masks,
+ hfgitr_feat_map, FEAT_FGT);
+
static const struct reg_bits_to_feat_map hafgrtr_feat_map[] = {
NEEDS_FEAT(HAFGRTR_EL2_AMEVTYPER115_EL0 |
HAFGRTR_EL2_AMEVTYPER114_EL0 |
@@ -765,6 +780,9 @@ static const struct reg_bits_to_feat_map hafgrtr_feat_map[] = {
FEAT_AMUv1),
};
+static const DECLARE_FEAT_MAP_FGT(hafgrtr_desc, hafgrtr_masks,
+ hafgrtr_feat_map, FEAT_FGT);
+
static const struct reg_bits_to_feat_map hfgitr2_feat_map[] = {
NEEDS_FEAT(HFGITR2_EL2_nDCCIVAPS, FEAT_PoPS),
NEEDS_FEAT(HFGITR2_EL2_TSBCSYNC, FEAT_TRBEv1p1)
@@ -1122,20 +1140,25 @@ static void __init check_feat_map(const struct reg_bits_to_feat_map *map,
str, mask ^ ~res0);
}
+static u64 reg_feat_map_bits(const struct reg_bits_to_feat_map *map)
+{
+ return map->flags & RES0_POINTER ? ~(*map->res0p) : map->bits;
+}
+
+static void __init check_reg_desc(const struct reg_feat_map_desc *r)
+{
+ check_feat_map(r->bit_feat_map, r->bit_feat_map_sz,
+ ~reg_feat_map_bits(&r->feat_map), r->name);
+}
+
void __init check_feature_map(void)
{
- check_feat_map(hfgrtr_feat_map, ARRAY_SIZE(hfgrtr_feat_map),
- hfgrtr_masks.res0, hfgrtr_masks.str);
- check_feat_map(hfgwtr_feat_map, ARRAY_SIZE(hfgwtr_feat_map),
- hfgwtr_masks.res0, hfgwtr_masks.str);
- check_feat_map(hfgitr_feat_map, ARRAY_SIZE(hfgitr_feat_map),
- hfgitr_masks.res0, hfgitr_masks.str);
- check_feat_map(hdfgrtr_feat_map, ARRAY_SIZE(hdfgrtr_feat_map),
- hdfgrtr_masks.res0, hdfgrtr_masks.str);
- check_feat_map(hdfgwtr_feat_map, ARRAY_SIZE(hdfgwtr_feat_map),
- hdfgwtr_masks.res0, hdfgwtr_masks.str);
- check_feat_map(hafgrtr_feat_map, ARRAY_SIZE(hafgrtr_feat_map),
- hafgrtr_masks.res0, hafgrtr_masks.str);
+ check_reg_desc(&hfgrtr_desc);
+ check_reg_desc(&hfgwtr_desc);
+ check_reg_desc(&hfgitr_desc);
+ check_reg_desc(&hdfgrtr_desc);
+ check_reg_desc(&hdfgwtr_desc);
+ check_reg_desc(&hafgrtr_desc);
check_feat_map(hcrx_feat_map, ARRAY_SIZE(hcrx_feat_map),
__HCRX_EL2_RES0, "HCRX_EL2");
check_feat_map(hcr_feat_map, ARRAY_SIZE(hcr_feat_map),
@@ -1190,7 +1213,7 @@ static u64 __compute_fixed_bits(struct kvm *kvm,
match = idreg_feat_match(kvm, &map[i]);
if (!match || (map[i].flags & FIXED_VALUE))
- val |= map[i].bits;
+ val |= reg_feat_map_bits(&map[i]);
}
return val;
@@ -1206,6 +1229,29 @@ static u64 compute_res0_bits(struct kvm *kvm,
require, exclude | FIXED_VALUE);
}
+static u64 compute_reg_res0_bits(struct kvm *kvm,
+ const struct reg_feat_map_desc *r,
+ unsigned long require, unsigned long exclude)
+
+{
+ u64 res0;
+
+ res0 = compute_res0_bits(kvm, r->bit_feat_map, r->bit_feat_map_sz,
+ require, exclude);
+
+ /*
+ * If computing FGUs, don't take RES0 or register existence
+ * into account -- we're not computing bits for the register
+ * itself.
+ */
+ if (!(exclude & NEVER_FGU)) {
+ res0 |= compute_res0_bits(kvm, &r->feat_map, 1, require, exclude);
+ res0 |= ~reg_feat_map_bits(&r->feat_map);
+ }
+
+ return res0;
+}
+
static u64 compute_fixed_bits(struct kvm *kvm,
const struct reg_bits_to_feat_map *map,
int map_size,
@@ -1223,30 +1269,24 @@ void compute_fgu(struct kvm *kvm, enum fgt_group_id fgt)
switch (fgt) {
case HFGRTR_GROUP:
- val |= compute_res0_bits(kvm, hfgrtr_feat_map,
- ARRAY_SIZE(hfgrtr_feat_map),
- 0, NEVER_FGU);
- val |= compute_res0_bits(kvm, hfgwtr_feat_map,
- ARRAY_SIZE(hfgwtr_feat_map),
- 0, NEVER_FGU);
+ val |= compute_reg_res0_bits(kvm, &hfgrtr_desc,
+ 0, NEVER_FGU);
+ val |= compute_reg_res0_bits(kvm, &hfgwtr_desc,
+ 0, NEVER_FGU);
break;
case HFGITR_GROUP:
- val |= compute_res0_bits(kvm, hfgitr_feat_map,
- ARRAY_SIZE(hfgitr_feat_map),
- 0, NEVER_FGU);
+ val |= compute_reg_res0_bits(kvm, &hfgitr_desc,
+ 0, NEVER_FGU);
break;
case HDFGRTR_GROUP:
- val |= compute_res0_bits(kvm, hdfgrtr_feat_map,
- ARRAY_SIZE(hdfgrtr_feat_map),
- 0, NEVER_FGU);
- val |= compute_res0_bits(kvm, hdfgwtr_feat_map,
- ARRAY_SIZE(hdfgwtr_feat_map),
- 0, NEVER_FGU);
+ val |= compute_reg_res0_bits(kvm, &hdfgrtr_desc,
+ 0, NEVER_FGU);
+ val |= compute_reg_res0_bits(kvm, &hdfgwtr_desc,
+ 0, NEVER_FGU);
break;
case HAFGRTR_GROUP:
- val |= compute_res0_bits(kvm, hafgrtr_feat_map,
- ARRAY_SIZE(hafgrtr_feat_map),
- 0, NEVER_FGU);
+ val |= compute_reg_res0_bits(kvm, &hafgrtr_desc,
+ 0, NEVER_FGU);
break;
case HFGRTR2_GROUP:
val |= compute_res0_bits(kvm, hfgrtr2_feat_map,
@@ -1282,39 +1322,27 @@ void get_reg_fixed_bits(struct kvm *kvm, enum vcpu_sysreg reg, u64 *res0, u64 *r
switch (reg) {
case HFGRTR_EL2:
- *res0 = compute_res0_bits(kvm, hfgrtr_feat_map,
- ARRAY_SIZE(hfgrtr_feat_map), 0, 0);
- *res0 |= hfgrtr_masks.res0;
+ *res0 = compute_reg_res0_bits(kvm, &hfgrtr_desc, 0, 0);
*res1 = HFGRTR_EL2_RES1;
break;
case HFGWTR_EL2:
- *res0 = compute_res0_bits(kvm, hfgwtr_feat_map,
- ARRAY_SIZE(hfgwtr_feat_map), 0, 0);
- *res0 |= hfgwtr_masks.res0;
+ *res0 = compute_reg_res0_bits(kvm, &hfgwtr_desc, 0, 0);
*res1 = HFGWTR_EL2_RES1;
break;
case HFGITR_EL2:
- *res0 = compute_res0_bits(kvm, hfgitr_feat_map,
- ARRAY_SIZE(hfgitr_feat_map), 0, 0);
- *res0 |= hfgitr_masks.res0;
+ *res0 = compute_reg_res0_bits(kvm, &hfgitr_desc, 0, 0);
*res1 = HFGITR_EL2_RES1;
break;
case HDFGRTR_EL2:
- *res0 = compute_res0_bits(kvm, hdfgrtr_feat_map,
- ARRAY_SIZE(hdfgrtr_feat_map), 0, 0);
- *res0 |= hdfgrtr_masks.res0;
+ *res0 = compute_reg_res0_bits(kvm, &hdfgrtr_desc, 0, 0);
*res1 = HDFGRTR_EL2_RES1;
break;
case HDFGWTR_EL2:
- *res0 = compute_res0_bits(kvm, hdfgwtr_feat_map,
- ARRAY_SIZE(hdfgwtr_feat_map), 0, 0);
- *res0 |= hdfgwtr_masks.res0;
+ *res0 = compute_reg_res0_bits(kvm, &hdfgwtr_desc, 0, 0);
*res1 = HDFGWTR_EL2_RES1;
break;
case HAFGRTR_EL2:
- *res0 = compute_res0_bits(kvm, hafgrtr_feat_map,
- ARRAY_SIZE(hafgrtr_feat_map), 0, 0);
- *res0 |= hafgrtr_masks.res0;
+ *res0 = compute_reg_res0_bits(kvm, &hafgrtr_desc, 0, 0);
*res1 = HAFGRTR_EL2_RES1;
break;
case HFGRTR2_EL2:
--
2.39.2
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