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 66B0B3264EF for ; Mon, 30 Mar 2026 14:49:24 +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=1774882164; cv=none; b=U+FUhqwHEsm3EmHAsDfF9keO4HhLn+t+elHqd30QqCGV5X4d8hvYeF6XGpce26EVEGUWVgU0O25YvL3pccjf2Q0/qjtcdSIYjL5A5YF0uji+L3xaoejQD/8zlA+MaOhF/5U6U3zM/JrKc6LgZ1Np86K9Da9bPYXpBCR3FCO849o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774882164; c=relaxed/simple; bh=kupY+rUTW2UPV/U5cwqqP9hhXbxo6oWLqyy18kOdLqI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=u64OarmSL3wmirrPspRZ7b7KmHZWAGIQh6gM1dvxG9DkdHq2wpNl1tEf5sn0YB9WPrpKNYdrdCp4HxuKojzp0mAIKeaudnGx3daSWuCBSnyaCQ3RR9cAHYVSikLu4dY7uK4b615Vqht+SilCAWCa43vLX+iifXj7VYpXzFAuA50= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PaU3wEqc; 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="PaU3wEqc" 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> 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. 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