Merge branch kvm-arm64/misc into kvmarm/next

* kvm-arm64/misc:
  : Miscellaneous updates
  :
  :  - Provide a command-line parameter to statically control the WFx trap
  :    selection in KVM
  :
  :  - Make sysreg masks allocation accounted
  Revert "KVM: arm64: nv: Fix RESx behaviour of disabled FGTs with negative polarity"
  KVM: arm64: nv: Use GFP_KERNEL_ACCOUNT for sysreg_masks allocation
  KVM: arm64: nv: Fix RESx behaviour of disabled FGTs with negative polarity
  KVM: arm64: Add early_param to control WFx trapping

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

3 files changed, 84 insertions, 4 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index b600df82669d..47249bd99987 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2745,6 +2745,24 @@
 			[KVM,ARM,EARLY] Allow use of GICv4 for direct
 			injection of LPIs.
 
+	kvm-arm.wfe_trap_policy=
+			[KVM,ARM] Control when to set WFE instruction trap for
+			KVM VMs. Traps are allowed but not guaranteed by the
+			CPU architecture.
+
+			trap: set WFE instruction trap
+
+			notrap: clear WFE instruction trap
+
+	kvm-arm.wfi_trap_policy=
+			[KVM,ARM] Control when to set WFI instruction trap for
+			KVM VMs. Traps are allowed but not guaranteed by the
+			CPU architecture.
+
+			trap: set WFI instruction trap
+
+			notrap: clear WFI instruction trap
+
 	kvm_cma_resv_ratio=n [PPC,EARLY]
 			Reserves given percentage from system memory area for
 			contiguous memory allocation for KVM hash pagetable
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 59716789fe0f..53e23528d2cf 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -48,6 +48,15 @@
 
 static enum kvm_mode kvm_mode = KVM_MODE_DEFAULT;
 
+enum kvm_wfx_trap_policy {
+	KVM_WFX_NOTRAP_SINGLE_TASK, /* Default option */
+	KVM_WFX_NOTRAP,
+	KVM_WFX_TRAP,
+};
+
+static enum kvm_wfx_trap_policy kvm_wfi_trap_policy __read_mostly = KVM_WFX_NOTRAP_SINGLE_TASK;
+static enum kvm_wfx_trap_policy kvm_wfe_trap_policy __read_mostly = KVM_WFX_NOTRAP_SINGLE_TASK;
+
 DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector);
 
 DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
@@ -546,6 +555,24 @@ static void vcpu_set_pauth_traps(struct kvm_vcpu *vcpu)
 	}
 }
 
+static bool kvm_vcpu_should_clear_twi(struct kvm_vcpu *vcpu)
+{
+	if (unlikely(kvm_wfi_trap_policy != KVM_WFX_NOTRAP_SINGLE_TASK))
+		return kvm_wfi_trap_policy == KVM_WFX_NOTRAP;
+
+	return single_task_running() &&
+	       (atomic_read(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe.vlpi_count) ||
+		vcpu->kvm->arch.vgic.nassgireq);
+}
+
+static bool kvm_vcpu_should_clear_twe(struct kvm_vcpu *vcpu)
+{
+	if (unlikely(kvm_wfe_trap_policy != KVM_WFX_NOTRAP_SINGLE_TASK))
+		return kvm_wfe_trap_policy == KVM_WFX_NOTRAP;
+
+	return single_task_running();
+}
+
 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
 	struct kvm_s2_mmu *mmu;
@@ -579,10 +606,15 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	if (kvm_arm_is_pvtime_enabled(&vcpu->arch))
 		kvm_make_request(KVM_REQ_RECORD_STEAL, vcpu);
 
-	if (single_task_running())
-		vcpu_clear_wfx_traps(vcpu);
+	if (kvm_vcpu_should_clear_twe(vcpu))
+		vcpu->arch.hcr_el2 &= ~HCR_TWE;
+	else
+		vcpu->arch.hcr_el2 |= HCR_TWE;
+
+	if (kvm_vcpu_should_clear_twi(vcpu))
+		vcpu->arch.hcr_el2 &= ~HCR_TWI;
 	else
-		vcpu_set_wfx_traps(vcpu);
+		vcpu->arch.hcr_el2 |= HCR_TWI;
 
 	vcpu_set_pauth_traps(vcpu);
 
@@ -2858,6 +2890,36 @@ static int __init early_kvm_mode_cfg(char *arg)
 }
 early_param("kvm-arm.mode", early_kvm_mode_cfg);
 
+static int __init early_kvm_wfx_trap_policy_cfg(char *arg, enum kvm_wfx_trap_policy *p)
+{
+	if (!arg)
+		return -EINVAL;
+
+	if (strcmp(arg, "trap") == 0) {
+		*p = KVM_WFX_TRAP;
+		return 0;
+	}
+
+	if (strcmp(arg, "notrap") == 0) {
+		*p = KVM_WFX_NOTRAP;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int __init early_kvm_wfi_trap_policy_cfg(char *arg)
+{
+	return early_kvm_wfx_trap_policy_cfg(arg, &kvm_wfi_trap_policy);
+}
+early_param("kvm-arm.wfi_trap_policy", early_kvm_wfi_trap_policy_cfg);
+
+static int __init early_kvm_wfe_trap_policy_cfg(char *arg)
+{
+	return early_kvm_wfx_trap_policy_cfg(arg, &kvm_wfe_trap_policy);
+}
+early_param("kvm-arm.wfe_trap_policy", early_kvm_wfe_trap_policy_cfg);
+
 enum kvm_mode kvm_get_mode(void)
 {
 	return kvm_mode;
diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c
index bae8536cbf00..d23618af8291 100644
--- a/arch/arm64/kvm/nested.c
+++ b/arch/arm64/kvm/nested.c
@@ -198,7 +198,7 @@ int kvm_init_nv_sysregs(struct kvm *kvm)
 		goto out;
 
 	kvm->arch.sysreg_masks = kzalloc(sizeof(*(kvm->arch.sysreg_masks)),
-					 GFP_KERNEL);
+					 GFP_KERNEL_ACCOUNT);
 	if (!kvm->arch.sysreg_masks) {
 		ret = -ENOMEM;
 		goto out;