From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 597A535E53A for ; Mon, 19 Jan 2026 12:47:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768826844; cv=none; b=cv6fbwKwYPePXayctiBtwUmN/EF8ia6Otth5pqgu96l/+qeEgYZy7r0kbwnLUrguUN/6S2iNexlN2Y7248Bdswe1ncOGuKkja50eEnH77q2LXA9PyalA4RG3augmbB5mK3ZFawwcVVx6Abdq1q1EHLoG0CeNxUf9nN/E6ghy7m8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768826844; c=relaxed/simple; bh=ufNwNnSfrHd6Z4/GzOKeFv+3tjFAU9R1kyG7siYhD68=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UDvBkdhIZ64k9/94x6TIlJmrOR2v6tIwk93fZH0PFpXzN7TpO2+R8AtAioCJVh6JJW/wnTETg++P3doDYiZ9KE3IgG7wG3ZMiILrG4awoEyhBdvpvrkSkkJZqeH5d7w5XDY59hSMt6qJ+Aq22tm8/QxBuukxSqU8wMV6k3ORiFE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TUzGfxrn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TUzGfxrn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75771C19424; Mon, 19 Jan 2026 12:47:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768826844; bh=ufNwNnSfrHd6Z4/GzOKeFv+3tjFAU9R1kyG7siYhD68=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TUzGfxrnzpudRB/fSHiC9+PbU7vJRCGKLv38QD1NmGqiYxCfD/6kIdh7vZz4Ch/O+ nadWVKsVqyEap/DOULNB/ib8jhcaXdw2FKZj9c/ibwqmW/cfBk0wYFbnTc9veR/Qy1 LcjKQSe9QBZzPLwuJmvsLbP0fzaQUcmLU1LMVqXTO9pEItOS4S7AtBCeeincshE9gg bw4EB43F46qu8y3Gww5tKVMKR0OySwUJyRQbln6kJRW3ObMUGyGevIZIYkQJQ5XPS3 WZR6+a3TyMm8TF2pfLUhzqCAdD0INkR5VHSV7YUEks5k7gLtmQPKU793wb7/U3hahR IURs9c9JVcYMg== From: Will Deacon To: kvmarm@lists.linux.dev Cc: linux-arm-kernel@lists.infradead.org, Will Deacon , Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Quentin Perret , Fuad Tabba , Vincent Donnefort , Mostafa Saleh Subject: [PATCH v2 10/35] KVM: arm64: Ignore -EAGAIN when mapping in pages for the pKVM host Date: Mon, 19 Jan 2026 12:46:03 +0000 Message-ID: <20260119124629.2563-11-will@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260119124629.2563-1-will@kernel.org> References: <20260119124629.2563-1-will@kernel.org> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit If the host takes a stage-2 translation fault on two CPUs at the same time, one of them will get back -EAGAIN from the page-table mapping code when it runs into the mapping installed by the other. Rather than handle this explicitly in handle_host_mem_abort(), pass the new KVM_PGTABLE_WALK_IGNORE_EAGAIN flag to kvm_pgtable_stage2_map() from __host_stage2_idmap() and return -EEXIST if host_stage2_adjust_range() finds a valid pte. This will avoid having to test for -EAGAIN on the reclaim path in subsequent patches. Signed-off-by: Will Deacon --- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 49db32f3ddf7..0abf6c3acdf7 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -459,8 +459,15 @@ static bool range_is_memory(u64 start, u64 end) static inline int __host_stage2_idmap(u64 start, u64 end, enum kvm_pgtable_prot prot) { + /* + * We don't make permission changes to the host idmap after + * initialisation, so we can squash -EAGAIN to save callers + * having to treat it like success in the case that they try to + * map something that is already mapped. + */ return kvm_pgtable_stage2_map(&host_mmu.pgt, start, end - start, start, - prot, &host_s2_pool, 0); + prot, &host_s2_pool, + KVM_PGTABLE_WALK_IGNORE_EAGAIN); } /* @@ -502,7 +509,7 @@ static int host_stage2_adjust_range(u64 addr, struct kvm_mem_range *range) return ret; if (kvm_pte_valid(pte)) - return -EAGAIN; + return -EEXIST; if (pte) { WARN_ON(addr_is_memory(addr) && @@ -607,7 +614,6 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt) { struct kvm_vcpu_fault_info fault; u64 esr, addr; - int ret = 0; esr = read_sysreg_el2(SYS_ESR); if (!__get_fault_info(esr, &fault)) { @@ -626,8 +632,13 @@ 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; - ret = host_stage2_idmap(addr); - BUG_ON(ret && ret != -EAGAIN); + switch (host_stage2_idmap(addr)) { + case -EEXIST: + case 0: + break; + default: + BUG(); + } } struct check_walk_data { -- 2.52.0.457.g6b5491de43-goog