diff options
| author | Oliver Upton <oliver.upton@linux.dev> | 2023-10-04 23:49:46 +0000 |
|---|---|---|
| committer | Oliver Upton <oliver.upton@linux.dev> | 2023-10-05 09:33:15 +0000 |
| commit | d34b76489ea0c6168d230d4f9ad065422ba5f6d6 (patch) | |
| tree | 3119655c62cbdf254dfc217333abfe3e594b09e8 /arch/arm64/kvm/hypercalls.c | |
| parent | bb17fb31f00ebd8df478a9533c6b77d6eebe6464 (diff) | |
KVM: arm64: Only insert reserved ranges when SMCCC filter is used
The reserved ranges are only useful for preventing userspace from
adding a rule that intersects with functions we must handle in KVM. If
userspace never writes to the SMCCC filter than this is all just wasted
work/memory.
Insert reserved ranges on the first call to KVM_ARM_VM_SMCCC_FILTER.
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231004234947.207507-3-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Diffstat (limited to 'arch/arm64/kvm/hypercalls.c')
| -rw-r--r-- | arch/arm64/kvm/hypercalls.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c index 35e023322cdb..20a878c64ba7 100644 --- a/arch/arm64/kvm/hypercalls.c +++ b/arch/arm64/kvm/hypercalls.c @@ -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 +146,20 @@ 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) @@ -189,6 +193,12 @@ static int kvm_smccc_set_filter(struct kvm *kvm, struct kvm_smccc_filter __user goto out_unlock; } + if (!kvm_smccc_filter_configured(kvm)) { + r = kvm_smccc_filter_insert_reserved(kvm); + if (WARN_ON_ONCE(r)) + goto out_unlock; + } + r = mtree_insert_range(&kvm->arch.smccc_filter, start, end, xa_mk_value(filter.action), GFP_KERNEL_ACCOUNT); if (r) @@ -392,7 +402,7 @@ 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) |