KVM: arm64: Move NV-specific capping to idreg sanitisation

Instead of applying the NV idreg limits at run time, switch to
doing it at the same time as the reset of the VM initialisation.

This will make things much simpler once we introduce vcpu-driven
variants of NV.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20250220134907.554085-10-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/include/asm/kvm_nested.h b/arch/arm64/include/asm/kvm_nested.h
index 56c4bcd35e2e5fae0c92b29cec338c53cf114585..692f403c1896e69c75886539f3cc4762fdb4c057 100644 (file)
--- a/arch/arm64/include/asm/kvm_nested.h
+++ b/arch/arm64/include/asm/kvm_nested.h
@@ -188,6 +188,7 @@ static inline bool kvm_supported_tlbi_s1e2_op(struct kvm_vcpu *vpcu, u32 instr)
 }
 
 int kvm_init_nv_sysregs(struct kvm_vcpu *vcpu);
+u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val);
 
 #ifdef CONFIG_ARM64_PTR_AUTH
 bool kvm_auth_eretax(struct kvm_vcpu *vcpu, u64 *elr);

diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c
index f0d7dd3615bbc93584a9a9092f1668300be345d9..409e5e67ae1e1a24537488cb06132e9da2b0d816 100644 (file)
--- a/arch/arm64/kvm/nested.c
+++ b/arch/arm64/kvm/nested.c
@@ -804,7 +804,7 @@ void kvm_arch_flush_shadow_all(struct kvm *kvm)
  * This list should get updated as new features get added to the NV
  * support, and new extension to the architecture.
  */
-static u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val)
+u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val)
 {
        switch (reg) {
        case SYS_ID_AA64ISAR0_EL1:
@@ -929,47 +929,6 @@ static u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val)
        return val;
 }
 
-static void limit_nv_id_regs(struct kvm *kvm)
-{
-       u64 val;
-
-       val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64ISAR0_EL1);
-       val = limit_nv_id_reg(kvm, SYS_ID_AA64ISAR0_EL1, val);
-       kvm_set_vm_id_reg(kvm, SYS_ID_AA64ISAR0_EL1, val);
-
-       val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64ISAR1_EL1);
-       val = limit_nv_id_reg(kvm, SYS_ID_AA64ISAR1_EL1, val);
-       kvm_set_vm_id_reg(kvm, SYS_ID_AA64ISAR1_EL1, val);
-
-       val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1);
-       val = limit_nv_id_reg(kvm, SYS_ID_AA64PFR0_EL1, val);
-       kvm_set_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1, val);
-
-       val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64PFR1_EL1);
-       val = limit_nv_id_reg(kvm, SYS_ID_AA64PFR1_EL1, val);
-       kvm_set_vm_id_reg(kvm, SYS_ID_AA64PFR1_EL1, val);
-
-       val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64MMFR0_EL1);
-       val = limit_nv_id_reg(kvm, SYS_ID_AA64MMFR0_EL1, val);
-       kvm_set_vm_id_reg(kvm, SYS_ID_AA64MMFR0_EL1, val);
-
-       val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64MMFR1_EL1);
-       val = limit_nv_id_reg(kvm, SYS_ID_AA64MMFR1_EL1, val);
-       kvm_set_vm_id_reg(kvm, SYS_ID_AA64MMFR1_EL1, val);
-
-       val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64MMFR2_EL1);
-       val = limit_nv_id_reg(kvm, SYS_ID_AA64MMFR2_EL1, val);
-       kvm_set_vm_id_reg(kvm, SYS_ID_AA64MMFR2_EL1, val);
-
-       val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64MMFR4_EL1);
-       val = limit_nv_id_reg(kvm, SYS_ID_AA64MMFR4_EL1, val);
-       kvm_set_vm_id_reg(kvm, SYS_ID_AA64MMFR4_EL1, val);
-
-       val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64DFR0_EL1);
-       val = limit_nv_id_reg(kvm, SYS_ID_AA64DFR0_EL1, val);
-       kvm_set_vm_id_reg(kvm, SYS_ID_AA64DFR0_EL1, val);
-}
-
 u64 kvm_vcpu_apply_reg_masks(const struct kvm_vcpu *vcpu,
                             enum vcpu_sysreg sr, u64 v)
 {
@@ -1014,8 +973,6 @@ int kvm_init_nv_sysregs(struct kvm_vcpu *vcpu)
        if (!kvm->arch.sysreg_masks)
                return -ENOMEM;
 
-       limit_nv_id_regs(kvm);
-
        /* VTTBR_EL2 */
        res0 = res1 = 0;
        if (!kvm_has_feat_enum(kvm, ID_AA64MMFR1_EL1, VMIDBits, 16))

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index db94d8a380331cc33b200dd297a12f1e98091aec..dacccc35a3bd5823d829603fa237a92304c8ab78 100644 (file)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1638,6 +1638,9 @@ static u64 __kvm_read_sanitised_id_reg(const struct kvm_vcpu *vcpu,
                break;
        }
 
+       if (vcpu_has_nv(vcpu))
+               val = limit_nv_id_reg(vcpu->kvm, id, val);
+
        return val;
 }