From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EB83C46E00B for ; Tue, 1 Sep 2026 08:09:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788250199; cv=none; b=dWZdnBEXcOFdALZacqv6MxU3YVI621izncrnYfKJcxu2PqZZjg2h6V4d07dF5s0NFfnrMcy2lJZFA0pX2KUjwZAOs8innEAXopVYxv9Y9kHTmvq6dUQI/M1zbhBZXITY5xyAKbUalTgq0/ly4pjLEx/1I+bqMXRjHNWJzZf3eok= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788250199; c=relaxed/simple; bh=525SXKtkJWipm/cY2EbI4t3ZCkAuK43q21NBlpiAGOI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=m0HhieZ0yvBflBJcQbjlsQ3MnzdBFmDEPmIWxTSld1DLdecell0GAsmygaRqCbv0hSVEzXrjhfNtmTXnp50pqkgrvs0E8VmsYbZY3KngNgyXeSq1xnoJCVCT+AU0gswrL1E5HYW7pAO+pHva6kXZelO2SjxWKFUJ3qAebqe72P8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=qGtkV2J6; arc=none smtp.client-ip=209.85.221.71 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="qGtkV2J6" Received: by mail-wr1-f71.google.com with SMTP id ffacd0b85a97d-47f6d70223dso3003297f8f.1 for ; Tue, 01 Sep 2026 01:09:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1788250196; x=1788854996; darn=lists.linux.dev; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=VQruuicz/6guQAq8w+QAJ7KPe6zCOEn9cupA41y8u7Y=; b=qGtkV2J6QqNW0+8HozojSCMjMHlm81Z0nkRKV6cLLAKPb2QErsr3TUUk3OSO0rPvaF ZNNWZKmUfK+N4wO6sW7kRWZAj0CsR/V5tZ1d/T0FpNsVXv4t5tuvN10tHDPCSwhrK+7O jxdfk9JzZcuN0ZwYtguhJNfGCBFq5Rqo47rab8noNO0tEQEzoULRUGIrQGls7DLH1g4P 0EgVwe53CjdBdHR4IFLhed+zMrFkVDRSxCBMgeDziBEcO/fjOsUn1Es1AuudBTF5TDou MuI1hBGV3yoynfERrTqRTxfEJcsRef7gdgt3uw6AoHraGUkFRb+0Aw4YfpEQ23w9f79f +Ckg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788250196; x=1788854996; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=VQruuicz/6guQAq8w+QAJ7KPe6zCOEn9cupA41y8u7Y=; b=f9S/SSwJWdnrjPQCDL5nIPMzoO+G+DquFjuaMu/o6b0DBJCwnRh770E9+y5uGWIh5M GdQ286SXT2zoW1zJf9bjo6O2YDHlP2RR5yTSY1nOxFA6Cf+HmsYwqEsUAqQrcKSQNRtr DFKEor+LFOXHusLC09ZvTZ9geuzD/GwQLfta33tr+KtMmrtKnjenGCe+umSCbg8tfG/g 7sAeQxy37fyELWZI1ygF75AlmE3+PznQGHmoIgqZ8Ta76SrBuecN2HeV0k/4VUD3wU8u mSRrvPVY+r9CIrFNfxBhPNDgc6j1UaQX7y4aNiP8asw2BHfCom9dB6vEZV9jyJNP1S5D ORwg== X-Forwarded-Encrypted: i=1; AKwUvBwFehX9LabZ4/DXhonQGUzxwm/4FrN1vGfJwNDuKqUaLTu0BNDs0SYQwyoIEs0Op9Ft7yeUJVA=@lists.linux.dev X-Gm-Message-State: AFuF++lYQNaqXp25q3jZF6lwRWm5HY/HtxtsonYonrl9K5uC1Oud1es4 GU1vLWCYhqGHDP+VexRDWmbV1fMyJ4LAgvOlo0kXsjIOJGV7kI3g1vB8zH4R52G3OIpQNpbAL0p KknlVXQH5g5qy/Jddm4xTAw== X-Received: from wrsc7.prod.google.com ([2002:adf:fb47:0:b0:47f:45e3:ffb0]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:adf:f68f:0:b0:482:f0ee:1390 with SMTP id ffacd0b85a97d-4844101d845mr9401575f8f.22.1788250195887; Tue, 01 Sep 2026 01:09:55 -0700 (PDT) Date: Tue, 1 Sep 2026 09:09:29 +0100 In-Reply-To: <20260901080941.997769-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260901080941.997769-1-vdonnefort@google.com> X-Mailer: git-send-email 2.55.0.897.gb25b4bd76c-goog Message-ID: <20260901080941.997769-7-vdonnefort@google.com> Subject: [PATCH v5 06/18] KVM: arm64: Add pkvm_hyp_req infrastructure From: Vincent Donnefort To: maz@kernel.org, oupton@kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org Cc: joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, kernel-team@android.com, fuad.tabba@linux.dev, qperret@google.com, Vincent Donnefort Content-Type: text/plain; charset="UTF-8" Introduce a struct pkvm_hyp_req to enable the pKVM hypervisor to request resources from the host. Provide serialisation helpers to transport these requests via SMCCC registers (starting from a2): pkvm_hyp_req_to_smccc() to encode into the SMCCC args. smccc_to_pkvm_hyp_req() to decode them. When the hypervisor raises a request, the host must handle it and retry the HVC. To automate this sequence, introduce the pkvm_call_hyp_req() macro. This intercepts pending requests, invokes the handler and retries the HVC. Additionally, introduce a trace event to track the handling of these requests. Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Signed-off-by: Vincent Donnefort diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h index beea00e693a0..19bddf261c82 100644 --- a/arch/arm64/include/asm/kvm_pkvm.h +++ b/arch/arm64/include/asm/kvm_pkvm.h @@ -205,6 +205,109 @@ struct pkvm_mapping { u64 __subtree_last; /* Internal member for interval tree */ }; +enum pkvm_hyp_req_type { + PKVM_HYP_NO_REQ = 0, + __PKVM_HYP_REQ_TYPE_MAX, +}; + +#define PKVM_HYP_REQ_SMCCC_ARG_SIZE_MAX \ + (sizeof(struct arm_smccc_res) - offsetof(struct arm_smccc_res, a2) - 1) + +struct pkvm_hyp_req { + u8 type; + union { + struct { + u32 nr_pages; + } mem; + struct { + /* Helper for SMCCC encoding/decoding */ + u8 args[PKVM_HYP_REQ_SMCCC_ARG_SIZE_MAX]; + } args; + }; +}; + +static inline size_t pkvm_hyp_req_arg_size(u8 type) +{ + switch (type) { + case PKVM_HYP_NO_REQ: + return 0; + default: + WARN_ON(1); + } + + return 0; +} + +/* Encode the pending pkvm_hyp_req type into the SMCCC args */ +static inline void +pkvm_hyp_req_to_smccc(struct kvm_cpu_context *host_ctxt, struct pkvm_hyp_req *req) +{ + u8 *dst, type = req->type; + size_t size; + + if (type == PKVM_HYP_NO_REQ || type >= __PKVM_HYP_REQ_TYPE_MAX) { + host_ctxt->regs.regs[2] = 0; + return; + } + + size = pkvm_hyp_req_arg_size(type); + if (WARN_ON(size > PKVM_HYP_REQ_SMCCC_ARG_SIZE_MAX)) + return; + + dst = (u8 *)&host_ctxt->regs.regs[2]; + *dst = type; + + memcpy(dst + 1, &req->args, size); +} + +/* Return true if a pkvm_hyp_req has been decoded from the SMCCC args */ +static inline bool smccc_to_pkvm_hyp_req(struct pkvm_hyp_req *req, struct arm_smccc_res *res) +{ + u8 *src = (u8 *)res + offsetof(struct arm_smccc_res, a2); + u8 type = *src; + + if (type == PKVM_HYP_NO_REQ || type >= __PKVM_HYP_REQ_TYPE_MAX) + return false; + + req->type = type; + memcpy(&req->args, src + 1, pkvm_hyp_req_arg_size(type)); + + return true; +} + +int __pkvm_handle_smccc_req(struct arm_smccc_res *res); + +/** + * pkvm_call_hyp_req() - Issue an HVC that can return hypervisor requests + * @f: Hypervisor function symbol to call. + * @...: Arguments to pass to the hypercall. + * + * Re-issue an HVC and process any pending hypervisor request until completion + * or error. + * + * Only use this helper for HVCs whose hypervisor handlers format their return + * registers with pkvm_hyp_req_to_smccc(). + * + * Return: Result of the hypercall or a negative error if the hyp request + * handling failed. + */ +#define pkvm_call_hyp_req(f, ...) \ +({ \ + struct arm_smccc_res __res; \ + int __ret; \ + do { \ + __ret = -1; \ + arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(f), ##__VA_ARGS__, &__res); \ + if (WARN_ON(__res.a0 != SMCCC_RET_SUCCESS)) \ + break; \ + __ret = __res.a1; \ + if (!__ret) \ + break; \ + __ret = __pkvm_handle_smccc_req(&__res); \ + } while (!__ret); \ + __ret; \ +}) + int pkvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu, struct kvm_pgtable_mm_ops *mm_ops); void pkvm_pgtable_stage2_destroy_range(struct kvm_pgtable *pgt, diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c index e5200731a45b..11d9e2f70cd8 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -16,6 +16,9 @@ #include "hyp_constants.h" +#define CREATE_TRACE_POINTS +#include "trace_pkvm.h" + DEFINE_STATIC_KEY_FALSE(kvm_protected_mode_initialized); static struct memblock_region *hyp_memory = kvm_nvhe_sym(hyp_memory); @@ -594,3 +597,25 @@ bool pkvm_force_reclaim_guest_page(phys_addr_t phys) return !ret || ret == -EAGAIN; } + +static int pkvm_handle_hyp_req(struct pkvm_hyp_req *req) +{ + int ret = -EINVAL; + + switch (req->type) { + } + + trace_kvm_handle_pkvm_hyp_req(req, ret); + + return ret; +} + +int __pkvm_handle_smccc_req(struct arm_smccc_res *res) +{ + struct pkvm_hyp_req req; + + if (smccc_to_pkvm_hyp_req(&req, res)) + return pkvm_handle_hyp_req(&req); + + return res->a1; +} diff --git a/arch/arm64/kvm/trace_pkvm.h b/arch/arm64/kvm/trace_pkvm.h new file mode 100644 index 000000000000..3966c111e3ad --- /dev/null +++ b/arch/arm64/kvm/trace_pkvm.h @@ -0,0 +1,43 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#if !defined(_TRACE_PKVM_ARM64_KVM_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_PKVM_ARM64_KVM_H + +#include +#include + +#undef TRACE_SYSTEM +#define TRACE_SYSTEM kvm + +TRACE_DEFINE_ENUM(PKVM_HYP_NO_REQ); + +#define PKVM_HYP_REQ_TYPES \ + { PKVM_HYP_NO_REQ, "NO_REQ" } + +TRACE_EVENT(kvm_handle_pkvm_hyp_req, + TP_PROTO(struct pkvm_hyp_req *req, int ret), + TP_ARGS(req, ret), + + TP_STRUCT__entry( + __field(u8, type) + __field(int, ret) + ), + + TP_fast_assign( + __entry->type = req->type; + __entry->ret = ret; + ), + + TP_printk("type: %s ret: %d", + __print_symbolic(__entry->type, PKVM_HYP_REQ_TYPES), + __entry->ret) +); + +#endif /* _TRACE_PKVM_ARM64_KVM_H */ + +#undef TRACE_INCLUDE_PATH +#define TRACE_INCLUDE_PATH . +#undef TRACE_INCLUDE_FILE +#define TRACE_INCLUDE_FILE trace_pkvm + +/* This part must be outside protection */ +#include -- 2.55.0.897.gb25b4bd76c-goog