Commit 25a35c1a authored by Oliver Upton's avatar Oliver Upton
Browse files

Merge branch kvm-arm64/smccc-filter-cleanups into kvmarm/next 



* kvm-arm64/smccc-filter-cleanups:
  : Cleanup the management of KVM's SMCCC maple tree
  :
  : Avoid the cost of maintaining the SMCCC filter maple tree if userspace
  : hasn't writen a rule to the filter. While at it, rip out the now
  : unnecessary VM flag to indicate whether or not the SMCCC filter was
  : configured.
  KVM: arm64: Use mtree_empty() to determine if SMCCC filter configured
  KVM: arm64: Only insert reserved ranges when SMCCC filter is used
  KVM: arm64: Add a predicate for testing if SMCCC filter is configured

Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parents 7ff7dfe9 4202bcac

arch/arm64/include/asm/kvm_host.h

+1 −3
Original line number Diff line number Diff line
@@ -239,10 +239,8 @@ struct kvm_arch { 
#define KVM_ARCH_FLAG_VM_COUNTER_OFFSET			5

	/* Timer PPIs made immutable */

#define KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE		6

	/* SMCCC filter initialized for the VM */

#define KVM_ARCH_FLAG_SMCCC_FILTER_CONFIGURED		7

	/* Initial ID reg values loaded */

#define KVM_ARCH_FLAG_ID_REGS_INITIALIZED		8

#define KVM_ARCH_FLAG_ID_REGS_INITIALIZED		7

	unsigned long flags;



	/* VM-wide vCPU feature set */

arch/arm64/kvm/hypercalls.c

+22 −12
Original line number Diff line number Diff line
@@ -133,12 +133,10 @@ static bool kvm_smccc_test_fw_bmap(struct kvm_vcpu *vcpu, u32 func_id) 
						   ARM_SMCCC_SMC_64,		\

						   0, ARM_SMCCC_FUNC_MASK)



static void init_smccc_filter(struct kvm *kvm)

static int kvm_smccc_filter_insert_reserved(struct kvm *kvm)

{

	int r;



	mt_init(&kvm->arch.smccc_filter);



	/*

	 * Prevent userspace from handling any SMCCC calls in the architecture

	 * range, avoiding the risk of misrepresenting Spectre mitigation status
@@ -148,14 +146,25 @@ static void init_smccc_filter(struct kvm *kvm) 
			       SMC32_ARCH_RANGE_BEGIN, SMC32_ARCH_RANGE_END,

			       xa_mk_value(KVM_SMCCC_FILTER_HANDLE),

			       GFP_KERNEL_ACCOUNT);

	WARN_ON_ONCE(r);

	if (r)

		goto out_destroy;



	r = mtree_insert_range(&kvm->arch.smccc_filter,

			       SMC64_ARCH_RANGE_BEGIN, SMC64_ARCH_RANGE_END,

			       xa_mk_value(KVM_SMCCC_FILTER_HANDLE),

			       GFP_KERNEL_ACCOUNT);

	WARN_ON_ONCE(r);

	if (r)

		goto out_destroy;



	return 0;

out_destroy:

	mtree_destroy(&kvm->arch.smccc_filter);

	return r;

}



static bool kvm_smccc_filter_configured(struct kvm *kvm)

{

	return !mtree_empty(&kvm->arch.smccc_filter);

}



static int kvm_smccc_set_filter(struct kvm *kvm, struct kvm_smccc_filter __user *uaddr)
@@ -184,13 +193,14 @@ static int kvm_smccc_set_filter(struct kvm *kvm, struct kvm_smccc_filter __user 
		goto out_unlock;

	}



	r = mtree_insert_range(&kvm->arch.smccc_filter, start, end,

			       xa_mk_value(filter.action), GFP_KERNEL_ACCOUNT);

	if (r)

	if (!kvm_smccc_filter_configured(kvm)) {

		r = kvm_smccc_filter_insert_reserved(kvm);

		if (WARN_ON_ONCE(r))

			goto out_unlock;

	}



	set_bit(KVM_ARCH_FLAG_SMCCC_FILTER_CONFIGURED, &kvm->arch.flags);



	r = mtree_insert_range(&kvm->arch.smccc_filter, start, end,

			       xa_mk_value(filter.action), GFP_KERNEL_ACCOUNT);

out_unlock:

	mutex_unlock(&kvm->arch.config_lock);

	return r;
@@ -201,7 +211,7 @@ static u8 kvm_smccc_filter_get_action(struct kvm *kvm, u32 func_id) 
	unsigned long idx = func_id;

	void *val;



	if (!test_bit(KVM_ARCH_FLAG_SMCCC_FILTER_CONFIGURED, &kvm->arch.flags))

	if (!kvm_smccc_filter_configured(kvm))

		return KVM_SMCCC_FILTER_HANDLE;



	/*
@@ -387,7 +397,7 @@ void kvm_arm_init_hypercalls(struct kvm *kvm) 
	smccc_feat->std_hyp_bmap = KVM_ARM_SMCCC_STD_HYP_FEATURES;

	smccc_feat->vendor_hyp_bmap = KVM_ARM_SMCCC_VENDOR_HYP_FEATURES;



	init_smccc_filter(kvm);

	mt_init(&kvm->arch.smccc_filter);

}



void kvm_arm_teardown_hypercalls(struct kvm *kvm)