From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f73.google.com (mail-ej1-f73.google.com [209.85.218.73]) (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 4CE4C2FB093 for ; Tue, 9 Sep 2025 07:24:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757402687; cv=none; b=CA695OXmIfhCo84giYBagOCCoOw4ll2rTX963Y2cd72R66Ch58WU2QIcTfdH+DaJOh+PWqGXwNndywSKKcunRzCysew1uy0cVJHpP/ND+kVJu+wBOPOwRlt+3ENOFUW3E1q62tWydKdAMKDFeHVAalE3EsesfwBtGB31qrNkGJc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757402687; c=relaxed/simple; bh=fGOOQa2CrVeIt/bnLsZAHUHbzVMy9YqZzR8wBqGgcfo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=koxiSwKSqroZtBATQjow5brSoTK2GjCwacRGrx5osVn2vVhOKxymIA3gcDg6deZmCWHaX9YCwPa2l7d9W0aKrPAVRm2KsNVrgPK1vNT4OZyFwATVQCpXyJCFiu7Y5/ZW5Qp7iV7inX1tSq0ptfgC3dZbHZSha2RCnvf2sS+YEkg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--tabba.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=U1aSEDXc; arc=none smtp.client-ip=209.85.218.73 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--tabba.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="U1aSEDXc" Received: by mail-ej1-f73.google.com with SMTP id a640c23a62f3a-b043abc86fdso419223566b.3 for ; Tue, 09 Sep 2025 00:24:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1757402683; x=1758007483; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=HBlatNZogSVtHgRUtoqflxLkmp73EbTbckKY3UHYcxQ=; b=U1aSEDXcITo1unLnk/xrD3CDrx2UvN+LZzhzbD83qhccrlfyrZuMBQsmCysdtp8Hhz UXMGJDTvgyeJ/7ZNFck8xYPH3RaRmasBGTQSO4qrn7klS6dZt0o1KqCOdbaLeDPZJ6W5 foadxG0yWAE3nd6rJeD6a4Z28jpY8P74mmtjDhgo8d3Ur0WdQsmqPP37Z28cn6zrcLn3 8It+1MVH2k+HiWsHqmFgYFWEmd+Zl9MlHZR0d0c2BMkhIHUXs6P/ACVjjk5tCnjxY2km 6HmF/YD9XRcit/+4oQkRorapwaA/sYz6qslU20+vb9I/WVDGgwC6D+amWjj2Gkf+qAlL 37EQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757402683; x=1758007483; h=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; bh=HBlatNZogSVtHgRUtoqflxLkmp73EbTbckKY3UHYcxQ=; b=iSeM5sdFjfKlR7ec9R8TGxXKg1bI/t934YwgaN6ULX0S142yrtpc7Id+tXurh5zOgl /51hsbi2n3pv3zwh8RC+WtuIh3SAxNmtsj/CTAav31mai3CDfqAy7WZ0AQf9iiHn3Tkz 14xvpeQBMixv+whg83uJ3yX8lDc70vMzyZf7jFyleNAU6fNHh0c1rCo9czlwUEHPZYPf 1us8uTgiVR7KPjHyWojmV5UQZbj8VKTV0pXSqz7vNz/GEm7hOE5w9wtdMPvAC6TbFaPH xcZJzCsA0PGXt5MlhjAZ6l0jJG7mLYIxtjM8LJsLqvXMa0OLLnQSKxkqhOHuZjR+/rh9 F4yg== X-Gm-Message-State: AOJu0YzmEzFvtbvPkY4ovf74gOj4j3xBejD/idVxN/I5fx9sKi3bsUaj 5vej3HOfeM8b6jSEvj9NbYqViuCpmiJU+QxTZmy6fGckDUMlq/tkPXYT4Qpd0Ez/I5P71TEOpyq habsmPcI7eYUkjrpVJVTvxZ8xr/EZqlCERq1gpRY3YhKMKv5Q00QihA/4RCT+685FL38VibqGCt ISrnr5EG26+L2aSqUdIAy55B6ib0L+YQA= X-Google-Smtp-Source: AGHT+IET6bM6myhOi9tNma3d70x70a1N88PiYCS8MHYHbKBvpAalmvpkEEEA/7N6Lbh2UFnO+rE1yFkjDA== X-Received: from ejcty8.prod.google.com ([2002:a17:907:c708:b0:b03:84d5:ce15]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a17:907:26c7:b0:b04:33a1:7f14 with SMTP id a640c23a62f3a-b04b1666d4fmr971382466b.35.1757402683174; Tue, 09 Sep 2025 00:24:43 -0700 (PDT) Date: Tue, 9 Sep 2025 08:24:33 +0100 In-Reply-To: <20250909072437.4110547-1-tabba@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250909072437.4110547-1-tabba@google.com> X-Mailer: git-send-email 2.51.0.384.g4c02a37b29-goog Message-ID: <20250909072437.4110547-7-tabba@google.com> Subject: [PATCH v4 6/9] KVM: arm64: Separate allocation and insertion of pKVM VM table entries From: Fuad Tabba To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org Cc: maz@kernel.org, oliver.upton@linux.dev, will@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, broonie@kernel.org, vdonnefort@google.com, qperret@google.com, sebastianene@google.com, keirf@google.com, smostafa@google.com, tabba@google.com Content-Type: text/plain; charset="UTF-8" The current insert_vm_table_entry() function performs two actions at once: it finds a free slot in the pKVM VM table and populates it with the pkvm_hyp_vm pointer. Refactor this function as a preparatory step for future work that will require reserving a VM slot and its corresponding handle earlier in the VM lifecycle, before the pkvm_hyp_vm structure is initialized and ready to be inserted. Split the function into a two-phase process: - A new allocate_vm_table_entry() function finds an empty slot, marks it as reserved with a RESERVED_ENTRY placeholder, and returns a handle derived from the slot's index. - The insert_vm_table_entry() function is repurposed to take the handle, validate that the corresponding slot is in the reserved state, and then populate it with the pkvm_hyp_vm pointer. Signed-off-by: Fuad Tabba --- arch/arm64/kvm/hyp/nvhe/pkvm.c | 52 ++++++++++++++++++++++++++++------ 1 file changed, 43 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index 969f6b293234..64b760d30d05 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -192,6 +192,11 @@ static int pkvm_vcpu_init_traps(struct pkvm_hyp_vcpu *hyp_vcpu) */ #define HANDLE_OFFSET 0x1000 +/* + * Marks a reserved but not yet used entry in the VM table. + */ +#define RESERVED_ENTRY ((void *)0xa110ca7ed) + static unsigned int vm_handle_to_idx(pkvm_handle_t handle) { return handle - HANDLE_OFFSET; @@ -231,6 +236,10 @@ static struct pkvm_hyp_vm *get_vm_by_handle(pkvm_handle_t handle) if (unlikely(idx >= KVM_MAX_PVMS)) return NULL; + /* A reserved entry doesn't represent an initialized VM. */ + if (unlikely(vm_table[idx] == RESERVED_ENTRY)) + return NULL; + return vm_table[idx]; } @@ -481,7 +490,7 @@ static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu, return ret; } -static int find_free_vm_table_entry(struct kvm *host_kvm) +static int find_free_vm_table_entry(void) { int i; @@ -494,15 +503,13 @@ static int find_free_vm_table_entry(struct kvm *host_kvm) } /* - * Allocate a VM table entry and insert a pointer to the new vm. + * Reserve a VM table entry. * * Return a unique handle to the VM on success, * negative error code on failure. */ -static pkvm_handle_t insert_vm_table_entry(struct kvm *host_kvm, - struct pkvm_hyp_vm *hyp_vm) +static int allocate_vm_table_entry(void) { - struct kvm_s2_mmu *mmu = &hyp_vm->kvm.arch.mmu; int idx; hyp_assert_lock_held(&vm_table_lock); @@ -515,10 +522,30 @@ static pkvm_handle_t insert_vm_table_entry(struct kvm *host_kvm, if (unlikely(!vm_table)) return -EINVAL; - idx = find_free_vm_table_entry(host_kvm); - if (idx < 0) + idx = find_free_vm_table_entry(); + if (unlikely(idx < 0)) return idx; + vm_table[idx] = RESERVED_ENTRY; + + return idx; +} + +/* + * Insert a pointer to the new VM into the VM table. + * + * Return 0 on success, or negative error code on failure. + */ +static int insert_vm_table_entry(struct kvm *host_kvm, + struct pkvm_hyp_vm *hyp_vm, + pkvm_handle_t handle) +{ + struct kvm_s2_mmu *mmu = &hyp_vm->kvm.arch.mmu; + unsigned int idx; + + hyp_assert_lock_held(&vm_table_lock); + + idx = vm_handle_to_idx(handle); hyp_vm->kvm.arch.pkvm.handle = idx_to_vm_handle(idx); /* VMID 0 is reserved for the host */ @@ -528,7 +555,7 @@ static pkvm_handle_t insert_vm_table_entry(struct kvm *host_kvm, mmu->pgt = &hyp_vm->pgt; vm_table[idx] = hyp_vm; - return hyp_vm->kvm.arch.pkvm.handle; + return 0; } /* @@ -614,6 +641,7 @@ int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva, struct pkvm_hyp_vm *hyp_vm = NULL; size_t vm_size, pgd_size; unsigned int nr_vcpus; + pkvm_handle_t handle; void *pgd = NULL; int ret; @@ -643,10 +671,16 @@ int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva, init_pkvm_hyp_vm(host_kvm, hyp_vm, nr_vcpus); hyp_spin_lock(&vm_table_lock); - ret = insert_vm_table_entry(host_kvm, hyp_vm); + ret = allocate_vm_table_entry(); if (ret < 0) goto err_unlock; + handle = idx_to_vm_handle(ret); + + ret = insert_vm_table_entry(host_kvm, hyp_vm, handle); + if (ret) + goto err_unlock; + ret = kvm_guest_prepare_stage2(hyp_vm, pgd); if (ret) goto err_remove_vm_table_entry; -- 2.51.0.384.g4c02a37b29-goog