From nobody Tue Dec 2 02:59:07 2025 Received: from mail-ej1-f74.google.com (mail-ej1-f74.google.com [209.85.218.74]) (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 495AE33344D for ; Mon, 17 Nov 2025 18:48:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763405321; cv=none; b=N08NubAiRyF8oGz1KHKDJMf4x2tskYC3VGktuGiI3K3h+RrQjEKIwtMLyotdDYi8qe81TyGGIueheSlebhU0dfrtExxxHqwo/1KgDlbWCZ1kJ+x3ep+mzit6oznu0N0Z1EA+FYD6bjKXJqRXYdVTr5E42pzVJkee2TwWtiq+F+U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763405321; c=relaxed/simple; bh=NAMroDrXjFET8e/V1jEPHTmEuoxT2nPqbJIpZ7VUQF4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=dfXxLe5w/brHhX/pDTUgBzRgCzPEyYl6YVaTv+c9r6x9ohSf6qVmw1zsBukdI9K1X7VK5N3BrSjagalQsSpQDrDVX6AchE3O3pSSHBhel9fJzn98/JtnpxJpZck9epbBXHmxLeTKDSwt3FED2B9LjhMeIrniGSwNHd1FqYmFcsk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--smostafa.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=S2VB/vK5; arc=none smtp.client-ip=209.85.218.74 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--smostafa.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="S2VB/vK5" Received: by mail-ej1-f74.google.com with SMTP id a640c23a62f3a-b726a3c3214so396789066b.2 for ; Mon, 17 Nov 2025 10:48:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1763405316; x=1764010116; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=Rk1fl88JutZZYCoKcXxRTtxtyt/5+rf5iGOfbus1BTk=; b=S2VB/vK5mh2Yn1+3ALzfnJKVVsSvEzR2V8K7B/tbaRb3g1YJoQ9VN9gydSAqd651FV 2LmEja+4sEQ//8B7/u/G4t80pL+vWmQQD6ji6yh8ppzA7mLtmm1a7fwow8QlLUwaWAWq v/euv4YuktyJbieUfpt8UN9A1/Yac/rN4HD7oTfVObOBQ7dunW8QOnTX1LfjqUaBQJ8M OEtOA7Z1jHqbuEcgOXainXjFYs1DiT0M/SzdAK2XDrRBthg5y/hA+MeGMgQxDoFSBEGW egbmP5FfS2+mLrLP3OOPDcdkIrP9fSa3nBDePJhY7CmuGblVW/+q0ei/r4rEJ7HE58OD yPfg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763405316; x=1764010116; 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=Rk1fl88JutZZYCoKcXxRTtxtyt/5+rf5iGOfbus1BTk=; b=RwjmyNVVFxdh5by2gGQWCfRFM1C83QgPudUFWgKpZQXqPfQki33w0M2ttJHLr/WORu rd5hP27drlzaz+lyBSRKqSxxJLFcErmFKZsGvQKa4D6s1yB7PMC6xNetB6Jn2GIAGuC1 S5Fp4QalFPA082S4Rlxoxr/9Y8TPtYkaSzyDx09qhvnA/z3lh65wVkVQJXUduNdf4E14 uTJv1gwAhHA4wlS8DTnn1kP6tmP2QlSnRKWyLXAjgoM6Eym9wcqOzfUG/jZ2Po6DvTha z42yllDe+6qWMWn7csUXDzwUZVREdIlYRWYBmHclBJmdE1M/27WN4neJFIA4IYxV55k6 y46Q== X-Forwarded-Encrypted: i=1; AJvYcCWysI0n0Uyager09t7/QYlAIs5NYBYfPRHhZdmJf5C87vm4aL/obt5XZbjs3o5l8v7thVcTviHao70qpVM=@vger.kernel.org X-Gm-Message-State: AOJu0Yxu+8vLkHcDcEuRGTyStcOlrgOkvlgVkFK4efFaS+K/ktqomRCn qOzEgYVitADL2gOTrS6hyeilJYDfVZmwaa4x+CVnOWA1cKr8RsLMNC4PKesvK73nrR5Ssp4P68b CWzB1TLdskiAnFQ== X-Google-Smtp-Source: AGHT+IFK6mFtucBRLiWaaV+YANl4dQaIe6ZXNzcjcMCQe/1qsUgD5bMWkFpnXRoT7wZjLhUKC6CSylQU/X+dYw== X-Received: from ejcvd5.prod.google.com ([2002:a17:907:d205:b0:b73:7a81:20af]) (user=smostafa job=prod-delivery.src-stubby-dispatcher) by 2002:a17:907:3c82:b0:b73:16fc:d469 with SMTP id a640c23a62f3a-b736793dcdcmr1369485766b.51.1763405316436; Mon, 17 Nov 2025 10:48:36 -0800 (PST) Date: Mon, 17 Nov 2025 18:47:57 +0000 In-Reply-To: <20251117184815.1027271-1-smostafa@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251117184815.1027271-1-smostafa@google.com> X-Mailer: git-send-email 2.52.0.rc1.455.g30608eb744-goog Message-ID: <20251117184815.1027271-11-smostafa@google.com> Subject: [PATCH v5 10/27] KVM: arm64: iommu: Add memory pool From: Mostafa Saleh To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, iommu@lists.linux.dev Cc: catalin.marinas@arm.com, will@kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, joro@8bytes.org, jean-philippe@linaro.org, jgg@ziepe.ca, praan@google.com, danielmentz@google.com, mark.rutland@arm.com, qperret@google.com, tabba@google.com, Mostafa Saleh Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" IOMMU drivers would require to allocate memory for the shadow page table. Similar to the host stage-2 CPU page table, the IOMMU pool is allocated early from the carveout and it's memory is added in a pool which the IOMMU driver can allocate from and reclaim at run time. As this is too early for drivers to use init calls, a default value can be set in the kernel config through IOMMU_POOL_PAGES, which then can be overridden later from the kernel command line: "kvm-arm.hyp_iommu_pages". Later when the driver registers, it will pass how many pages it needs, and if it was less than what was allocated, it will fail to register. Signed-off-by: Mostafa Saleh --- .../admin-guide/kernel-parameters.txt | 4 +++ arch/arm64/include/asm/kvm_host.h | 3 +- arch/arm64/kvm/Kconfig | 7 +++++ arch/arm64/kvm/hyp/include/nvhe/iommu.h | 5 ++- arch/arm64/kvm/hyp/nvhe/iommu/iommu.c | 20 +++++++++++- arch/arm64/kvm/hyp/nvhe/setup.c | 16 +++++++++- arch/arm64/kvm/iommu.c | 31 ++++++++++++++++++- arch/arm64/kvm/pkvm.c | 1 + 8 files changed, 82 insertions(+), 5 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentatio= n/admin-guide/kernel-parameters.txt index 6c42061ca20e..f843d10a3dfc 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3059,6 +3059,10 @@ trap: set WFI instruction trap =20 notrap: clear WFI instruction trap + kvm-arm.hyp_iommu_pages=3D + [KVM, ARM, EARLY] + Number of pages allocated for the IOMMU pool from the + KVM carveout when running in protected mode. =20 kvm_cma_resv_ratio=3Dn [PPC,EARLY] Reserves given percentage from system memory area for diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm= _host.h index fb2551ba8798..5496c52d0163 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -1654,7 +1654,8 @@ static __always_inline enum fgt_group_id __fgt_reg_to= _group_id(enum vcpu_sysreg =20 #ifndef __KVM_NVHE_HYPERVISOR__ struct kvm_iommu_ops; -int kvm_iommu_register_driver(struct kvm_iommu_ops *hyp_ops); +int kvm_iommu_register_driver(struct kvm_iommu_ops *hyp_ops, size_t pool_p= ages); +size_t kvm_iommu_pages(void); #endif =20 #endif /* __ARM64_KVM_HOST_H__ */ diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index 4f803fd1c99a..6a1bd82a0d07 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -83,4 +83,11 @@ config PTDUMP_STAGE2_DEBUGFS =20 If in doubt, say N. =20 +config IOMMU_POOL_PAGES + hex "Number of pages reserved for IOMMU pool" + depends on KVM && IOMMU_SUPPORT + default 0x0 + help + IOMMU pool is used with protected mode to allocated IOMMU drivers page = tables. + endif # VIRTUALIZATION diff --git a/arch/arm64/kvm/hyp/include/nvhe/iommu.h b/arch/arm64/kvm/hyp/i= nclude/nvhe/iommu.h index 219363045b1c..9f4906c6dcc9 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/iommu.h +++ b/arch/arm64/kvm/hyp/include/nvhe/iommu.h @@ -10,8 +10,11 @@ struct kvm_iommu_ops { void (*host_stage2_idmap)(phys_addr_t start, phys_addr_t end, int prot); }; =20 -int kvm_iommu_init(void); +int kvm_iommu_init(void *pool_base, size_t nr_pages); =20 void kvm_iommu_host_stage2_idmap(phys_addr_t start, phys_addr_t end, enum kvm_pgtable_prot prot); +void *kvm_iommu_donate_pages(u8 order); +void kvm_iommu_reclaim_pages(void *ptr); + #endif /* __ARM64_KVM_NVHE_IOMMU_H__ */ diff --git a/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c b/arch/arm64/kvm/hyp/nvh= e/iommu/iommu.c index 414bd4c97690..a0df34ecf6b0 100644 --- a/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c +++ b/arch/arm64/kvm/hyp/nvhe/iommu/iommu.c @@ -15,6 +15,7 @@ struct kvm_iommu_ops *kvm_iommu_ops; =20 /* Protected by host_mmu.lock */ static bool kvm_idmap_initialized; +static struct hyp_pool iommu_pages_pool; =20 static inline int pkvm_to_iommu_prot(enum kvm_pgtable_prot prot) { @@ -72,7 +73,7 @@ static int kvm_iommu_snapshot_host_stage2(void) return ret; } =20 -int kvm_iommu_init(void) +int kvm_iommu_init(void *pool_base, size_t nr_pages) { int ret; =20 @@ -80,6 +81,13 @@ int kvm_iommu_init(void) !kvm_iommu_ops->host_stage2_idmap) return -ENODEV; =20 + if (nr_pages) { + ret =3D hyp_pool_init(&iommu_pages_pool, hyp_virt_to_pfn(pool_base), + nr_pages, 0); + if (ret) + return ret; + } + ret =3D kvm_iommu_ops->init(); if (ret) return ret; @@ -95,3 +103,13 @@ void kvm_iommu_host_stage2_idmap(phys_addr_t start, phy= s_addr_t end, return; kvm_iommu_ops->host_stage2_idmap(start, end, pkvm_to_iommu_prot(prot)); } + +void *kvm_iommu_donate_pages(u8 order) +{ + return hyp_alloc_pages(&iommu_pages_pool, order); +} + +void kvm_iommu_reclaim_pages(void *ptr) +{ + hyp_put_page(&iommu_pages_pool, ptr); +} diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setu= p.c index de79803e7439..c245ea88c480 100644 --- a/arch/arm64/kvm/hyp/nvhe/setup.c +++ b/arch/arm64/kvm/hyp/nvhe/setup.c @@ -22,6 +22,13 @@ =20 unsigned long hyp_nr_cpus; =20 +/* See kvm_iommu_pages() */ +#ifdef CONFIG_IOMMU_POOL_PAGES +size_t hyp_kvm_iommu_pages =3D CONFIG_IOMMU_POOL_PAGES; +#else +size_t hyp_kvm_iommu_pages; +#endif + #define hyp_percpu_size ((unsigned long)__per_cpu_end - \ (unsigned long)__per_cpu_start) =20 @@ -33,6 +40,7 @@ static void *selftest_base; static void *ffa_proxy_pages; static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops; static struct hyp_pool hpool; +static void *iommu_base; =20 static int divide_memory_pool(void *virt, unsigned long size) { @@ -70,6 +78,12 @@ static int divide_memory_pool(void *virt, unsigned long = size) if (!ffa_proxy_pages) return -ENOMEM; =20 + if (hyp_kvm_iommu_pages) { + iommu_base =3D hyp_early_alloc_contig(hyp_kvm_iommu_pages); + if (!iommu_base) + return -ENOMEM; + } + return 0; } =20 @@ -329,7 +343,7 @@ void __noreturn __pkvm_init_finalise(void) if (ret) goto out; =20 - ret =3D kvm_iommu_init(); + ret =3D kvm_iommu_init(iommu_base, hyp_kvm_iommu_pages); if (ret) goto out; =20 diff --git a/arch/arm64/kvm/iommu.c b/arch/arm64/kvm/iommu.c index c9041dcb6c57..6143fd3e1de3 100644 --- a/arch/arm64/kvm/iommu.c +++ b/arch/arm64/kvm/iommu.c @@ -7,9 +7,38 @@ #include =20 extern struct kvm_iommu_ops *kvm_nvhe_sym(kvm_iommu_ops); +extern size_t kvm_nvhe_sym(hyp_kvm_iommu_pages); =20 -int kvm_iommu_register_driver(struct kvm_iommu_ops *hyp_ops) +int kvm_iommu_register_driver(struct kvm_iommu_ops *hyp_ops, size_t pool_p= ages) { + /* See kvm_iommu_pages() */ + if (pool_pages > kvm_nvhe_sym(hyp_kvm_iommu_pages)) { + kvm_err("Missing memory for the IOMMU pool, need 0x%zx pages, check kvm-= arm.hyp_iommu_pages", + pool_pages); + return -ENOMEM; + } + kvm_nvhe_sym(kvm_iommu_ops) =3D hyp_ops; return 0; } + +size_t kvm_iommu_pages(void) +{ + /* + * This is called very early during setup_arch() where no initcalls, + * so this has to call specific functions per each KVM driver. + * So we allow a config option that can set the defaul value for + * the IOMMU pool that can overridden by a command line option. + * When the driver registers it will pass the number pages needed + * for it's page tables, if less that what the system has already + * allocated we fail. + */ + return kvm_nvhe_sym(hyp_kvm_iommu_pages); +} + +/* Number of pages to reserve for iommu pool*/ +static int __init early_hyp_iommu_pages(char *arg) +{ + return kstrtoul(arg, 10, &kvm_nvhe_sym(hyp_kvm_iommu_pages)); +} +early_param("kvm-arm.hyp_iommu_pages", early_hyp_iommu_pages); diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c index 24f0f8a8c943..b9d212b48c04 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -63,6 +63,7 @@ void __init kvm_hyp_reserve(void) hyp_mem_pages +=3D hyp_vmemmap_pages(STRUCT_HYP_PAGE_SIZE); hyp_mem_pages +=3D pkvm_selftest_pages(); hyp_mem_pages +=3D hyp_ffa_proxy_pages(); + hyp_mem_pages +=3D kvm_iommu_pages(); =20 /* * Try to allocate a PMD-aligned region to reduce TLB pressure once --=20 2.52.0.rc1.455.g30608eb744-goog