From: Marc Zyngier Date: Tue, 14 Apr 2026 16:05:28 +0000 (+0100) Subject: KVM: arm64: pkvm: Adopt MARKER() to define host hypercall ranges X-Git-Tag: v7.1-rc2~26^2~1^2~9 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f05799491d6a2a29d8e15f4451e685c4a6e13d8f;p=thirdparty%2Fkernel%2Flinux.git KVM: arm64: pkvm: Adopt MARKER() to define host hypercall ranges The EL2 code defines ranges of host hypercalls that are either enabled at boot-time only, used by [nh]VHE KVM, or reserved to pKVM. The way these ranges are delineated is error prone, as the enum symbols defining the limits are expressed in terms of actual function symbols. This means that should a new function be added, special care must be taken to also update the limit symbol. Improve this by reusing the mechanism introduced for the vcpu_sysreg enum, which uses a MARKER() macro and some extra trickery to make the limit symbol standalone. Crucially, the limit symbol has the same value as the *following* symbol. The handle_host_hcall() function is then updated to make use of the new limit definitions and get rid of the brittle default upper limit. This allows for some more strict checks at build time, and the removal of an comparison at run time. Tested-by: Fuad Tabba Reviewed-by: Fuad Tabba Link: https://patch.msgid.link/20260414160528.2218858-1-maz@kernel.org Signed-off-by: Marc Zyngier --- diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 11dcdf434971..043495f7fc78 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -50,6 +50,9 @@ #include +#define MARKER(m) \ + m, __after_##m = m - 1 + enum __kvm_host_smccc_func { /* Hypercalls that are unavailable once pKVM has finalised. */ /* __KVM_HOST_SMCCC_FUNC___kvm_hyp_init */ @@ -59,8 +62,10 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___kvm_enable_ssbs, __KVM_HOST_SMCCC_FUNC___vgic_v3_init_lrs, __KVM_HOST_SMCCC_FUNC___vgic_v3_get_gic_config, + + MARKER(__KVM_HOST_SMCCC_FUNC_MIN_PKVM), + __KVM_HOST_SMCCC_FUNC___pkvm_prot_finalize, - __KVM_HOST_SMCCC_FUNC_MIN_PKVM = __KVM_HOST_SMCCC_FUNC___pkvm_prot_finalize, /* Hypercalls that are always available and common to [nh]VHE/pKVM. */ __KVM_HOST_SMCCC_FUNC___kvm_adjust_pc, @@ -84,7 +89,8 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___vgic_v3_restore_vmcr_aprs, __KVM_HOST_SMCCC_FUNC___vgic_v5_save_apr, __KVM_HOST_SMCCC_FUNC___vgic_v5_restore_vmcr_apr, - __KVM_HOST_SMCCC_FUNC_MAX_NO_PKVM = __KVM_HOST_SMCCC_FUNC___vgic_v5_restore_vmcr_apr, + + MARKER(__KVM_HOST_SMCCC_FUNC_PKVM_ONLY), /* Hypercalls that are available only when pKVM has finalised. */ __KVM_HOST_SMCCC_FUNC___pkvm_host_share_hyp, @@ -108,6 +114,8 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___pkvm_vcpu_load, __KVM_HOST_SMCCC_FUNC___pkvm_vcpu_put, __KVM_HOST_SMCCC_FUNC___pkvm_tlb_flush_vmid, + + MARKER(__KVM_HOST_SMCCC_FUNC_MAX) }; #define DECLARE_KVM_VHE_SYM(sym) extern char sym[] diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 851f6171751c..44211e86f5eb 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -450,9 +450,6 @@ struct kvm_vcpu_fault_info { r = __VNCR_START__ + ((VNCR_ ## r) / 8), \ __after_##r = __MAX__(__before_##r - 1, r) -#define MARKER(m) \ - m, __after_##m = m - 1 - enum vcpu_sysreg { __INVALID_SYSREG__, /* 0 is reserved as an invalid value */ MPIDR_EL1, /* MultiProcessor Affinity Register */ diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 8f7582d57ab5..1de9c70599c6 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -748,9 +748,11 @@ static const hcall_t host_hcall[] = { static void handle_host_hcall(struct kvm_cpu_context *host_ctxt) { DECLARE_REG(unsigned long, id, host_ctxt, 0); - unsigned long hcall_min = 0, hcall_max = -1; + unsigned long hcall_min = 0, hcall_max = __KVM_HOST_SMCCC_FUNC_MAX; hcall_t hfn; + BUILD_BUG_ON(ARRAY_SIZE(host_hcall) != __KVM_HOST_SMCCC_FUNC_MAX); + /* * If pKVM has been initialised then reject any calls to the * early "privileged" hypercalls. Note that we cannot reject @@ -763,16 +765,14 @@ static void handle_host_hcall(struct kvm_cpu_context *host_ctxt) if (static_branch_unlikely(&kvm_protected_mode_initialized)) { hcall_min = __KVM_HOST_SMCCC_FUNC_MIN_PKVM; } else { - hcall_max = __KVM_HOST_SMCCC_FUNC_MAX_NO_PKVM; + hcall_max = __KVM_HOST_SMCCC_FUNC_PKVM_ONLY; } id &= ~ARM_SMCCC_CALL_HINTS; id -= KVM_HOST_SMCCC_ID(0); - if (unlikely(id < hcall_min || id > hcall_max || - id >= ARRAY_SIZE(host_hcall))) { + if (unlikely(id < hcall_min || id >= hcall_max)) goto inval; - } hfn = host_hcall[id]; if (unlikely(!hfn))