From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 181C81061B06 for ; Mon, 30 Mar 2026 14:49:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=4dwi5pCAg/MZTNDHoKdZDmYR5Cl5fK1dAgs4M7cLrNQ=; b=TToJW+NX2i4GbCSm95YsLYgOR4 f0Gr7TI9D5JGAYzXTAPnC/3hGnpsJmaLecQUna3FdEXFs2mZ+rhZE5CpkRI0ew7CKjHuZY4gs5GRZ 2mtfm4CzphCYqpk7oi/FD4EKk2/jcJzlb2w2Zqrl/ra6GwfkS3Tqjt/AjBfAn0/JEbb/cWErdWETT gohst4Sfrvo09rPRQwYOupBtgYB9CldS7C2VRfbmFRMzVEEBZZ91WNsJNtsKyYhWM4tIrvh+qsH+w cN/+n4sKN8smVWAxzOl4NnwIWG98qYLUZPzkKSWQiSWHOX4mwCbOp+uNx3+IJJ+3oHZK5DOFfgCiE f4d4k0Uw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w7Dvm-0000000BT8i-3mfj; Mon, 30 Mar 2026 14:49:30 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w7Dvh-0000000BT55-0hJR for linux-arm-kernel@lists.infradead.org; Mon, 30 Mar 2026 14:49:25 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 957A560054; Mon, 30 Mar 2026 14:49:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8AD6AC4CEF7; Mon, 30 Mar 2026 14:49:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774882164; bh=kupY+rUTW2UPV/U5cwqqP9hhXbxo6oWLqyy18kOdLqI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PaU3wEqcUCRAhv1+1jIXQ1xovdIHMPnSQLXpYHLkXiFtgzFVMTYYQTXJ/1VK9rHhj lPtXW3MtGBM2I9hvClmBhrRGHPz/VrbarbLUUzGEbDt9jtuGggznNO+uwGsX6t3Kt1 D0/XMs7lCHRkuw/0ocJH/SJEPZQ6/jtohHQxfzz/LvAu4z+yh8PyW2QrZpw0eJ5Xkf o11L/yLkIsvs3o7YHyd3YgWqNKRuPI4SebdXFqEzxqS/XJnwMajL4Mm2y9FZ4G2XsX 9slyRC7SiLtOknPCaiN5Yh1MFMjMqYn6xgRf52mdevRe15IW7Rzdu8zZN2e0HFPSrl z9WDuTTAHQEQw== 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 , Alexandru Elisei Subject: [PATCH v5 10/38] KVM: arm64: Ignore -EAGAIN when mapping in pages for the pKVM host Date: Mon, 30 Mar 2026 15:48:11 +0100 Message-ID: <20260330144841.26181-11-will@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260330144841.26181-1-will@kernel.org> References: <20260330144841.26181-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 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. Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba Tested-by: Mostafa Saleh 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 d815265bd374..7d22893ab1dc 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -461,8 +461,15 @@ 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); } /* @@ -504,7 +511,7 @@ 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) && @@ -609,7 +616,6 @@ 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)) { @@ -628,8 +634,13 @@ 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 { -- 2.53.0.1018.g2bb0e51243-goog