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 4AD16F33A78 for ; Thu, 5 Mar 2026 14:44:49 +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=VGPJFYLBzm6Tz/ttEIhKsbug8LLNq+Z9GhS2kObL3jE=; b=wn7QrEHar6x642PIQWL1c6he17 l24qKK5kaxm6VEiGGC1cgRBbJ5oL2ootpOHyMoxEILSX6I7Yv8lZiWRnPUueMVpLDjHadsKOb+884 0KBTTEb1Mnrz4WaeGjtng4H1xIaRZFiqWj+ghWngZauat4U4K9WrcKBJh2JPVu7F92uDNedQiiWSV SMR9hg2bFV740CY6iUVlSvU/ZHfV1DHRS6q3RW96bdpxwGMZtzhqOsIxtBA0DOOyUb2+a/RGmisA6 N4aHbJH4PALeJ4lj+BCAQRx0AQyAVJ+X6RIbzomN+YxvCIOl17XIPZ1TiDi7vLUd5PmAWdFIREPrQ dPUg5q6w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vy9wT-000000021Jd-0QJJ; Thu, 05 Mar 2026 14:44:45 +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 1vy9wR-000000021I1-07wU for linux-arm-kernel@lists.infradead.org; Thu, 05 Mar 2026 14:44:43 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 74DF861851; Thu, 5 Mar 2026 14:44:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49AE5C116C6; Thu, 5 Mar 2026 14:44:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772721882; bh=A98jBFfJ0Zw8odIv9cujR5a6XKhnf74/r1VWTBluNWU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UGMcUolr9sRhY8akUwGcfiaq0SmE6b+jSfPDHR5YoLTLAPt7Fep3zIl5L7Z6HCvrU XRJhT1L3CS47R2uOm7taehQIKj4KdK45VCtCLMEx9ACImYlaWR4P8WCzZakKKLkGic ddzfFET6ZHHY16voHtNH15A8NJttx7iPEmRVVbuEo4u/U7Nf81uir0CZfKZIOLxWOE xvX11t6BvSQyQ2y6weRNdipt768j+XBSbwqHhl3J2KMXBI59J1/F0dwE/UXYHw0axC s5XFbmtjM7a2eo8/ykfXo22uALsw7EMbPKH1vU3/A0JAXNYU1zSExpirefyFMGM4D1 q0WfGiF3+VSZw== 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 v3 09/36] KVM: arm64: Ignore -EAGAIN when mapping in pages for the pKVM host Date: Thu, 5 Mar 2026 14:43:22 +0000 Message-ID: <20260305144351.17071-10-will@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260305144351.17071-1-will@kernel.org> References: <20260305144351.17071-1-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. 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 38f66a56a766..7b0f8ad7b20f 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 { -- 2.53.0.473.g4a7958ca14-goog