Re: [PATCH 13/20] KVM: arm64: Move RESx into individual register descriptors

Instead of hacking the RES1 bits at runtime, move them into the
register descriptors. This makes it significantly nicer.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/config.c | 36 +++++++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/config.c b/arch/arm64/kvm/config.c
index 7063fffc22799..d5871758f1fcc 100644
--- a/arch/arm64/kvm/config.c
+++ b/arch/arm64/kvm/config.c

@@ -30,6 +30,7 @@ struct reg_bits_to_feat_map {
 #define        RES0_WHEN_E2H1  BIT(7)  /* RES0 when E2H=1 and not supported */
 #define        RES1_WHEN_E2H0  BIT(8)  /* RES1 when E2H=0 and not supported */
 #define        RES1_WHEN_E2H1  BIT(9)  /* RES1 when E2H=1 and not supported */
+#define        FORCE_RESx      BIT(10) /* Unconditional RESx */

        unsigned long   flags;

@@ -107,6 +108,11 @@ struct reg_feat_map_desc {
  */
 #define NEEDS_FEAT(m, ...)     NEEDS_FEAT_FLAG(m, 0, __VA_ARGS__)

+/* Declare fixed RESx bits */
+#define FORCE_RES0(m)          NEEDS_FEAT_FLAG(m, FORCE_RESx, enforce_resx)
+#define FORCE_RES1(m)          NEEDS_FEAT_FLAG(m, FORCE_RESx | AS_RES1, \
+                                               enforce_resx)
+
 /*
  * Declare the dependency between a non-FGT register, a set of
  * feature, and the set of individual bits it contains. This generates

@@ -230,6 +236,15 @@ struct reg_feat_map_desc {
 #define FEAT_HCX               ID_AA64MMFR1_EL1, HCX, IMP
 #define FEAT_S2PIE             ID_AA64MMFR3_EL1, S2PIE, IMP

+static bool enforce_resx(struct kvm *kvm)
+{
+       /*
+        * Returning false here means that the RESx bits will be always
+        * addded to the fixed set bit. Yes, this is counter-intuitive.

+
 static bool not_feat_aa64el3(struct kvm *kvm)
 {
        return !kvm_has_feat(kvm, FEAT_AA64EL3);

@@ -1009,6 +1024,8 @@ static const struct reg_bits_to_feat_map hcr_feat_map[] = {
                   HCR_EL2_TWEDEn,
                   FEAT_TWED),
        NEEDS_FEAT_FIXED(HCR_EL2_E2H, compute_hcr_e2h),
+       FORCE_RES0(HCR_EL2_RES0),
+       FORCE_RES1(HCR_EL2_RES1),
 };

 static const DECLARE_FEAT_MAP(hcr_desc, HCR_EL2,

@@ -1029,6 +1046,8 @@ static const struct reg_bits_to_feat_map sctlr2_feat_map[] = {
                   SCTLR2_EL1_CPTM      |
                   SCTLR2_EL1_CPTM0,
                   FEAT_CPA2),
+       FORCE_RES0(SCTLR2_EL1_RES0),
+       FORCE_RES1(SCTLR2_EL1_RES1),
 };

 static const DECLARE_FEAT_MAP(sctlr2_desc, SCTLR2_EL1,

@@ -1054,6 +1073,8 @@ static const struct reg_bits_to_feat_map tcr2_el2_feat_map[] = {
                   TCR2_EL2_E0POE,
                   FEAT_S1POE),
        NEEDS_FEAT(TCR2_EL2_PIE, FEAT_S1PIE),
+       FORCE_RES0(TCR2_EL2_RES0),
+       FORCE_RES1(TCR2_EL2_RES1),
 };

 static const DECLARE_FEAT_MAP(tcr2_el2_desc, TCR2_EL2,

@@ -1131,6 +1152,8 @@ static const struct reg_bits_to_feat_map sctlr_el1_feat_map[] = {
                   SCTLR_EL1_A          |
                   SCTLR_EL1_M,
                   FEAT_AA64EL1),
+       FORCE_RES0(SCTLR_EL1_RES0),
+       FORCE_RES1(SCTLR_EL1_RES1),
 };

 static const DECLARE_FEAT_MAP(sctlr_el1_desc, SCTLR_EL1,

@@ -1165,6 +1188,8 @@ static const struct reg_bits_to_feat_map mdcr_el2_feat_map[] = {
                   MDCR_EL2_TDE         |
                   MDCR_EL2_TDRA,
                   FEAT_AA64EL1),
+       FORCE_RES0(MDCR_EL2_RES0),
+       FORCE_RES1(MDCR_EL2_RES1),
 };

 static const DECLARE_FEAT_MAP(mdcr_el2_desc, MDCR_EL2,

@@ -1203,6 +1228,8 @@ static const struct reg_bits_to_feat_map vtcr_el2_feat_map[] = {
                   VTCR_EL2_SL0         |
                   VTCR_EL2_T0SZ,
                   FEAT_AA64EL1),
+       FORCE_RES0(VTCR_EL2_RES0),
+       FORCE_RES1(VTCR_EL2_RES1),
 };

 static const DECLARE_FEAT_MAP(vtcr_el2_desc, VTCR_EL2,

@@ -1214,7 +1241,8 @@ static void __init check_feat_map(const struct reg_bits_to_feat_map *map,
        u64 mask = 0;

        for (int i = 0; i < map_size; i++)
-               mask |= map[i].bits;
+               if (!(map[i].flags & FORCE_RESx))
+                       mask |= map[i].bits;

        if (mask != ~resx)
                kvm_err("Undefined %s behaviour, bits %016llx\n",

@@ -1447,28 +1475,22 @@ struct resx get_reg_fixed_bits(struct kvm *kvm, enum vcpu_sysreg reg)
                break;
        case HCR_EL2:
                resx = compute_reg_resx_bits(kvm, &hcr_desc, 0, 0);
-               resx.res1 |= HCR_EL2_RES1;
                break;
        case SCTLR2_EL1:
        case SCTLR2_EL2:
                resx = compute_reg_resx_bits(kvm, &sctlr2_desc, 0, 0);
-               resx.res1 |= SCTLR2_EL1_RES1;
                break;
        case TCR2_EL2:
                resx = compute_reg_resx_bits(kvm, &tcr2_el2_desc, 0, 0);
-               resx.res1 |= TCR2_EL2_RES1;
                break;
        case SCTLR_EL1:
                resx = compute_reg_resx_bits(kvm, &sctlr_el1_desc, 0, 0);
-               resx.res1 |= SCTLR_EL1_RES1;
                break;
        case MDCR_EL2:
                resx = compute_reg_resx_bits(kvm, &mdcr_el2_desc, 0, 0);
-               resx.res1 |= MDCR_EL2_RES1;
                break;
        case VTCR_EL2:
                resx = compute_reg_resx_bits(kvm, &vtcr_el2_desc, 0, 0);
-               resx.res1 |= VTCR_EL2_RES1;
                break;
        default:
                WARN_ON_ONCE(1);
--

2.47.3