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Wed, 20 May 2026 08:27:21 -0700 (PDT) Date: Wed, 20 May 2026 16:26:40 +0100 In-Reply-To: <20260520152650.4107895-1-vdonnefort@google.com> Mime-Version: 1.0 References: <20260520152650.4107895-1-vdonnefort@google.com> X-Mailer: git-send-email 2.54.0.631.ge1b05301d1-goog Message-ID: <20260520152650.4107895-8-vdonnefort@google.com> Subject: [PATCH 07/17] KVM: arm64: Add pkvm_hyp_req infrastructure From: Vincent Donnefort To: maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, kernel-team@android.com, qperret@google.com, tabba@google.com, Vincent Donnefort Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260520_162736_831518_6BF6128B X-CRM114-Status: GOOD ( 19.09 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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. Signed-off-by: Vincent Donnefort diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h index 879f1667ec67..fb4d140c99cc 100644 --- a/arch/arm64/include/asm/kvm_pkvm.h +++ b/arch/arm64/include/asm/kvm_pkvm.h @@ -204,6 +204,95 @@ 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->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); + +#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 7abdc250b633..ce96a6f90bd0 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); @@ -108,6 +111,28 @@ static int pkvm_hyp_topup(enum pkvm_topup_id id, unsigned long nr_pages) return res.a1; } +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; +} + static void __pkvm_destroy_hyp_vm(struct kvm *kvm) { if (pkvm_hyp_vm_is_created(kvm)) { diff --git a/arch/arm64/kvm/trace_pkvm.h b/arch/arm64/kvm/trace_pkvm.h new file mode 100644 index 000000000000..4bf57c12e7de --- /dev/null +++ b/arch/arm64/kvm/trace_pkvm.h @@ -0,0 +1,37 @@ +/* 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_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: %u ret: %d", + __entry->type, __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 -- 2.54.0.631.ge1b05301d1-goog