KVM: arm64: Move existing feature disabling over to FGU infrastructure

We already trap a bunch of existing features for the purpose of
disabling them (MAIR2, POR, ACCDATA, SME...).

Let's move them over to our brand new FGU infrastructure.

Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240214131827.2856277-20-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index c69b258fc989be8c7647f79353d2bb8c780bf1cc..968a997b3f02804a255b0002bbbbe4e252df5cb6 100644 (file)
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -297,6 +297,8 @@ struct kvm_arch {
 #define KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE             6
        /* Initial ID reg values loaded */
 #define KVM_ARCH_FLAG_ID_REGS_INITIALIZED              7
+       /* Fine-Grained UNDEF initialised */
+#define KVM_ARCH_FLAG_FGU_INITIALIZED                  8
        unsigned long flags;
 
        /* VM-wide vCPU feature set */
@@ -1107,6 +1109,8 @@ int __init populate_nv_trap_config(void);
 bool lock_all_vcpus(struct kvm *kvm);
 void unlock_all_vcpus(struct kvm *kvm);
 
+void kvm_init_sysreg(struct kvm_vcpu *);
+
 /* MMIO helpers */
 void kvm_mmio_write_buf(void *buf, unsigned int len, unsigned long data);
 unsigned long kvm_mmio_read_buf(const void *buf, unsigned int len);

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index c063e84fc72c763409d4202d3d556620277e41d9..9f806c9b7d5d46a6e33171d738523e81470ad6d6 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -675,6 +675,12 @@ int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
                        return ret;
        }
 
+       /*
+        * This needs to happen after NV has imposed its own restrictions on
+        * the feature set
+        */
+       kvm_init_sysreg(vcpu);
+
        ret = kvm_timer_enable(vcpu);
        if (ret)
                return ret;

diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index a09149fd91ed25aff11286182f0b518df3f68229..245f9c1ca6660bc739d657dffbefaf7b0d07b927 100644 (file)
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -157,7 +157,7 @@ static inline void __activate_traps_hfgxtr(struct kvm_vcpu *vcpu)
 {
        struct kvm_cpu_context *hctxt = &this_cpu_ptr(&kvm_host_data)->host_ctxt;
        struct kvm *kvm = kern_hyp_va(vcpu->kvm);
-       u64 r_clr = 0, w_clr = 0, r_set = 0, w_set = 0, tmp;
+       u64 r_clr = 0, w_clr = 0, r_set = 0, w_set = 0;
        u64 r_val, w_val;
 
        CHECK_FGT_MASKS(HFGRTR_EL2);
@@ -174,13 +174,6 @@ static inline void __activate_traps_hfgxtr(struct kvm_vcpu *vcpu)
        ctxt_sys_reg(hctxt, HFGRTR_EL2) = read_sysreg_s(SYS_HFGRTR_EL2);
        ctxt_sys_reg(hctxt, HFGWTR_EL2) = read_sysreg_s(SYS_HFGWTR_EL2);
 
-       if (cpus_have_final_cap(ARM64_SME)) {
-               tmp = HFGxTR_EL2_nSMPRI_EL1_MASK | HFGxTR_EL2_nTPIDR2_EL0_MASK;
-
-               r_clr |= tmp;
-               w_clr |= tmp;
-       }
-
        /*
         * Trap guest writes to TCR_EL1 to prevent it from enabling HA or HD.
         */
@@ -195,15 +188,11 @@ static inline void __activate_traps_hfgxtr(struct kvm_vcpu *vcpu)
        compute_undef_clr_set(vcpu, kvm, HFGRTR_EL2, r_clr, r_set);
        compute_undef_clr_set(vcpu, kvm, HFGWTR_EL2, w_clr, w_set);
 
-       /* The default to trap everything not handled or supported in KVM. */
-       tmp = HFGxTR_EL2_nAMAIR2_EL1 | HFGxTR_EL2_nMAIR2_EL1 | HFGxTR_EL2_nS2POR_EL1 |
-             HFGxTR_EL2_nPOR_EL1 | HFGxTR_EL2_nPOR_EL0 | HFGxTR_EL2_nACCDATA_EL1;
-
-       r_val = __HFGRTR_EL2_nMASK & ~tmp;
+       r_val = __HFGRTR_EL2_nMASK;
        r_val |= r_set;
        r_val &= ~r_clr;
 
-       w_val = __HFGWTR_EL2_nMASK & ~tmp;
+       w_val = __HFGWTR_EL2_nMASK;
        w_val |= w_set;
        w_val &= ~w_clr;
 

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 938df5dc36841cae1025e9ae844e273dcb431bc7..39e7c7f7471754c8929972353c047527005ca671 100644 (file)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -3942,6 +3942,29 @@ int kvm_vm_ioctl_get_reg_writable_masks(struct kvm *kvm, struct reg_mask_range *
        return 0;
 }
 
+void kvm_init_sysreg(struct kvm_vcpu *vcpu)
+{
+       struct kvm *kvm = vcpu->kvm;
+
+       mutex_lock(&kvm->arch.config_lock);
+
+       if (test_bit(KVM_ARCH_FLAG_FGU_INITIALIZED, &kvm->arch.flags))
+               goto out;
+
+       kvm->arch.fgu[HFGxTR_GROUP] = (HFGxTR_EL2_nAMAIR2_EL1           |
+                                      HFGxTR_EL2_nMAIR2_EL1            |
+                                      HFGxTR_EL2_nS2POR_EL1            |
+                                      HFGxTR_EL2_nPOR_EL1              |
+                                      HFGxTR_EL2_nPOR_EL0              |
+                                      HFGxTR_EL2_nACCDATA_EL1          |
+                                      HFGxTR_EL2_nSMPRI_EL1_MASK       |
+                                      HFGxTR_EL2_nTPIDR2_EL0_MASK);
+
+       set_bit(KVM_ARCH_FLAG_FGU_INITIALIZED, &kvm->arch.flags);
+out:
+       mutex_unlock(&kvm->arch.config_lock);
+}
+
 int __init kvm_sys_reg_table_init(void)
 {
        struct sys_reg_params params;