From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) (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 9F42B47F3DE for ; Thu, 15 Oct 2026 20:09:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792094966; cv=none; b=taEjn+30wvRe2YyE1cbKAnZr0zynw5ixEka1rQXmL/dQqSaY0Ksj2WxTm7SjUo54TrXJ/8mPo3bv2wjNhWC5ACy59BOs7mn/2m8UbGaGkjbm3lW6nRabkAK5DzxlZ0O8BLx6hnwnMDKRwDDeRT+hLcNi5AJCrrBI8eY+jxI1xME= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792094966; c=relaxed/simple; bh=3vT4+pcdhJcVD4Z3oSn11IvY9+bAtQf3X3KAWQIbuE0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=nb+Ub0WgZVih79JiksexF2/OrnRm3wN4KH2lT6Jo+QAWUp5ic0DXzjX/9PeZguoqhYB2WBReAjN69xRnbZwnI2CkWh4DOKiNGCub5tHG1Pi3DhmvsUfTZNr/6bYep0ptyzCwmVnTeD9yoQv7HRHPVenXnmXurrkGWRzqHiJDvK8= 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=t+n3tSiO; arc=none smtp.client-ip=209.85.128.71 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--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="t+n3tSiO" Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-4a1b11e7837so26387665e9.1 for ; Thu, 15 Oct 2026 13:09:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1792094961; x=1792699761; 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=laM6+wZiNuYMQDtQzAoP4s+131ogUMmRLEJwdwwKDsc=; b=t+n3tSiOUT8TjdTc3priaRr2fPQVKJNJyOLUV7PlpBAWbHggQXXsD0HDO08dB4XAkq LnT/cdyjkwyxhmSjJ1gjcFlRI/3knFjVUuSQ/um0pkN2pKWSPrAvu6x1PowhXsEOM6po SuO/xf9WiNXEP4vumF8wz7Laa3cpzrVipt3PVnvC+2OtTYlCEuyXmx/z3CAqermHXT1i uC9yujo/Qefp6c1tckgfaXX5vvD+y5zkwhv3i1JlOMRW8pprux+QliTyCoqhbuwGnU2V lyH9XVNRyl8RSmaKClh4uCKzeIvi4LrK53QOvKftF6l5Q045p2Eh2LFNdm0K2dWMl7Tq FeLQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1792094961; x=1792699761; 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=laM6+wZiNuYMQDtQzAoP4s+131ogUMmRLEJwdwwKDsc=; b=tQKJFUSxurM6A2NQ9vzru4Yu1pwQLbylEyJJplx/JOj+0p9+qLkTb4QoXj2J8ye4uT 1POeb7FP07Tnqw+cpbdYxY9V4Q1gHqzgE+wNkx5WidhV/gZ2gE0ys3VjMk8U7Y6PXL0I MfahvHhK0ftLMsuAjRWuOReUGv0p36pjdsXB6AexywZpEelueZhCBNjc2DF1N79F246B qcJ5DULtgrRXlTC3tN+LLf5jkArha1JS9S9FGtewKOUTwa5mos4caWSF/D/ZDP1MJWBz JteWtzV9xE/ucI2T5qGNFt/ifbDkuTAfYcXj0zGYfeTwig3cV4x7izjP3akIUisf3Evb YTlw== X-Forwarded-Encrypted: i=1; AKwUvBzfb/tNcZOP05j0xEPB+udJor1Uw/mVncaHavuLGzltUWy2x6xbjEVKaD79M8bDRk77QPR69w==@lists.linux.dev X-Gm-Message-State: AFq9FYK1sMy0IcYoGdlBCdzrnpB/YqE6f3G58iT25uoTg1PCOPTgs231 /nGL3gyQO2aeuyXzyPx3vTNxVtJtX7yvhIFOhKJbF4sNFISlIJFzdE4t6VBaw4cxp6SYpSRenYP 5UMhPRvD84RBatA== X-Received: from wmbd8.prod.google.com ([2002:a05:600c:58c8:b0:4a1:8444:ff6d]) (user=smostafa job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:4e4a:b0:4a1:ac66:6ac8 with SMTP id 5b1f17b1804b1-4a1c7fa065fmr12093425e9.4.1792094961525; Thu, 15 Oct 2026 13:09:21 -0700 (PDT) Date: Thu, 15 Oct 2026 20:08:40 +0000 In-Reply-To: <20261015200903.2735565-1-smostafa@google.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20261015200903.2735565-1-smostafa@google.com> X-Mailer: git-send-email 2.56.0.176.g3575e65682-goog Message-ID: <20261015200903.2735565-10-smostafa@google.com> Subject: [PATCH v9 09/25] KVM: arm64: iommu: Support DABT for IOMMU 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, jgg@ziepe.ca, mark.rutland@arm.com, qperret@google.com, tabba@google.com, vdonnefort@google.com, nicolinc@nvidia.com, Mostafa Saleh Content-Type: text/plain; charset="UTF-8" The pKVM SMMUv3 driver emulates the SMMU registers for the host: the MMIO is donated to the hypervisor so that host accesses trap, and the hypervisor performs or rejects each access on the host's behalf. Add a dabt_handler op and call it from the host data abort path for aborts with a valid instruction syndrome on non-memory addresses. If the driver emulates the access, skip the faulting instruction, otherwise take the normal path, where hyp-owned MMIO is denied. Only aborts with a valid instruction syndrome can be emulated, so the host must access emulated registers with single-register loads and stores (readl/writel and friends). Signed-off-by: Mostafa Saleh --- arch/arm64/kvm/hyp/include/nvhe/iommu.h | 9 +++++++++ arch/arm64/kvm/hyp/nvhe/iommu.c | 6 ++++++ arch/arm64/kvm/hyp/nvhe/mem_protect.c | 17 +++++++++++++++++ 3 files changed, 32 insertions(+) diff --git a/arch/arm64/kvm/hyp/include/nvhe/iommu.h b/arch/arm64/kvm/hyp/include/nvhe/iommu.h index acd5058ef3ed..bd6604f194b5 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/iommu.h +++ b/arch/arm64/kvm/hyp/include/nvhe/iommu.h @@ -13,6 +13,13 @@ struct pkvm_iommu_ops { * with the same @prot, which must succeed. */ int (*host_stage2_idmap)(phys_addr_t start, phys_addr_t end, int prot); + /* + * Emulate a host data abort on MMIO @addr + * @esr has a valid instruction syndrome and @regs holds the host x0-x30, + * SRT 31 is the zero register. Return true if the access was emulated, + * which would skip the instruction. + */ + bool (*dabt_handler)(struct user_pt_regs *regs, u64 esr, u64 addr); }; int pkvm_iommu_init(void *pool_base, unsigned int nr_pages); @@ -25,4 +32,6 @@ void *pkvm_iommu_alloc_pages(u8 order); /* Free pages from pkvm_iommu_alloc_pages(). */ void pkvm_iommu_free_pages(void *ptr); +bool pkvm_iommu_host_dabt_handler(struct user_pt_regs *regs, u64 esr, u64 addr); + #endif /* __ARM64_KVM_NVHE_IOMMU_H__ */ diff --git a/arch/arm64/kvm/hyp/nvhe/iommu.c b/arch/arm64/kvm/hyp/nvhe/iommu.c index 36432bd46c78..cdf6e87bb68e 100644 --- a/arch/arm64/kvm/hyp/nvhe/iommu.c +++ b/arch/arm64/kvm/hyp/nvhe/iommu.c @@ -149,3 +149,9 @@ void pkvm_iommu_free_pages(void *ptr) { hyp_put_page(&iommu_pages_pool, ptr); } + +bool pkvm_iommu_host_dabt_handler(struct user_pt_regs *regs, u64 esr, u64 addr) +{ + return pkvm_iommu_ops && pkvm_iommu_ops->dabt_handler && + pkvm_iommu_ops->dabt_handler(regs, esr, addr); +} diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index c14af6a4877c..523bb6bd793b 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -13,6 +13,7 @@ #include #include +#include #include #include @@ -778,6 +779,12 @@ static void host_inject_mem_abort(struct kvm_cpu_context *host_ctxt) inject_host_exception(esr); } +static bool is_dabt_with_isv(u64 esr) +{ + return (ESR_ELx_EC(esr) == ESR_ELx_EC_DABT_LOW) && + (esr & ESR_ELx_ISV); +} + void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt) { struct kvm_vcpu_fault_info fault; @@ -800,6 +807,16 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt) BUG_ON(!(fault.hpfar_el2 & HPFAR_EL2_NS)); addr = FIELD_GET(HPFAR_EL2_FIPA, fault.hpfar_el2) << 12; + /* + * Let the IOMMU driver emulate accesses to its MMIO. + */ + if (is_dabt_with_isv(esr) && !addr_is_memory(addr) && + pkvm_iommu_host_dabt_handler(&host_ctxt->regs, esr, + addr | FAR_TO_FIPA_OFFSET(fault.far_el2))) { + kvm_skip_host_instr(); + return; + } + switch (host_stage2_idmap(addr)) { case -EPERM: host_inject_mem_abort(host_ctxt); -- 2.56.0.176.g3575e65682-goog