From patchwork Tue Oct 28 19:36:45 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Rutland X-Patchwork-Id: 5179311 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 7C933C11AC for ; Tue, 28 Oct 2014 19:40:56 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 727A420179 for ; Tue, 28 Oct 2014 19:40:55 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D3F9920176 for ; Tue, 28 Oct 2014 19:40:50 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XjCaE-0007M3-Kv; Tue, 28 Oct 2014 19:37:34 +0000 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XjCaA-0007Ku-JP for linux-arm-kernel@lists.infradead.org; Tue, 28 Oct 2014 19:37:31 +0000 Received: from leverpostej.cambridge.arm.com (leverpostej.cambridge.arm.com [10.1.205.151]) by cam-admin0.cambridge.arm.com (8.12.6/8.12.6) with ESMTP id s9SJaxwo013417; Tue, 28 Oct 2014 19:36:59 GMT From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] arm64: KVM: fix unmapping with 48-bit VAs Date: Tue, 28 Oct 2014 19:36:45 +0000 Message-Id: <1414525005-21080-1-git-send-email-mark.rutland@arm.com> X-Mailer: git-send-email 1.9.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141028_123731_028306_07158FE6 X-CRM114-Status: GOOD ( 16.02 ) X-Spam-Score: -5.6 (-----) Cc: Mark Rutland , Catalin Marinas , Jungseok Lee , Christoffer Dall , Marc Zyngier X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hi All, I'm not at all familiar with this code, so my analysis below might be off. Does this look right or am I just masking a more fundamental issue? I've given this a go with 4KiB pages on Juno with {39,48}-bit VAs and the system seems to boot fine. Thanks, Mark. ---->8---- Currently if using a 48-bit VA, tearing down the hyp page tables (which can happen in the absence of a GICH or GICV resource) results in the rather nasty splat below, evidently becasue we access a table that doesn't actually exist. Commit 38f791a4e499792e (arm64: KVM: Implement 48 VA support for KVM EL2 and Stage-2) added a pgd_none check to __create_hyp_mappings to account for the additional level of tables, but didn't add a corresponding check to unmap_range, and this seems to be the source of the problem. This patch adds the missing pgd_none check, ensuring we don't try to access tables that don't exist. Original splat below: kvm [1]: Using HYP init bounce page @83fe94a000 kvm [1]: Cannot obtain GICH resource Unable to handle kernel paging request at virtual address ffff7f7fff000000 pgd = ffff800000770000 [ffff7f7fff000000] *pgd=0000000000000000 Internal error: Oops: 96000004 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 1 Comm: swapper/0 Not tainted 3.18.0-rc2+ #89 task: ffff8003eb500000 ti: ffff8003eb45c000 task.ti: ffff8003eb45c000 PC is at unmap_range+0x120/0x580 LR is at free_hyp_pgds+0xac/0xe4 pc : [] lr : [] pstate: 80000045 sp : ffff8003eb45fbf0 x29: ffff8003eb45fbf0 x28: ffff800000736000 x27: ffff800000735000 x26: ffff7f7fff000000 x25: 0000000040000000 x24: ffff8000006f5000 x23: 0000000000000000 x22: 0000007fffffffff x21: 0000800000000000 x20: 0000008000000000 x19: 0000000000000000 x18: ffff800000648000 x17: ffff800000537228 x16: 0000000000000000 x15: 000000000000001f x14: 0000000000000000 x13: 0000000000000001 x12: 0000000000000020 x11: 0000000000000062 x10: 0000000000000006 x9 : 0000000000000000 x8 : 0000000000000063 x7 : 0000000000000018 x6 : 00000003ff000000 x5 : ffff800000744188 x4 : 0000000000000001 x3 : 0000000040000000 x2 : ffff800000000000 x1 : 0000007fffffffff x0 : 000000003fffffff Process swapper/0 (pid: 1, stack limit = 0xffff8003eb45c058) Stack: (0xffff8003eb45fbf0 to 0xffff8003eb460000) fbe0: eb45fcb0 ffff8003 0009cad8 ffff8000 fc00: 00000000 00000080 00736140 ffff8000 00736000 ffff8000 00000000 00007c80 fc20: 00000000 00000080 006f5000 ffff8000 00000000 00000080 00743000 ffff8000 fc40: 00735000 ffff8000 006d3030 ffff8000 006fe7b8 ffff8000 00000000 00000080 fc60: ffffffff 0000007f fdac1000 ffff8003 fd94b000 ffff8003 fda47000 ffff8003 fc80: 00502b40 ffff8000 ff000000 ffff7f7f fdec6000 00008003 fdac1630 ffff8003 fca0: eb45fcb0 ffff8003 ffffffff 0000007f eb45fd00 ffff8003 0009b378 ffff8000 fcc0: ffffffea 00000000 006fe000 ffff8000 00736728 ffff8000 00736120 ffff8000 fce0: 00000040 00000000 00743000 ffff8000 006fe7b8 ffff8000 0050cd48 00000000 fd00: eb45fd60 ffff8003 00096070 ffff8000 006f06e0 ffff8000 006f06e0 ffff8000 fd20: fd948b40 ffff8003 0009a320 ffff8000 00000000 00000000 00000000 00000000 fd40: 00000ae0 00000000 006aa25c ffff8000 eb45fd60 ffff8003 0017ca44 00000002 fd60: eb45fdc0 ffff8003 0009a33c ffff8000 006f06e0 ffff8000 006f06e0 ffff8000 fd80: fd948b40 ffff8003 0009a320 ffff8000 00000000 00000000 00735000 ffff8000 fda0: 006d3090 ffff8000 006aa25c ffff8000 00735000 ffff8000 006d3030 ffff8000 fdc0: eb45fdd0 ffff8003 000814c0 ffff8000 eb45fe50 ffff8003 006aaac4 ffff8000 fde0: 006ddd90 ffff8000 00000006 00000000 006d3000 ffff8000 00000095 00000000 fe00: 006a1e90 ffff8000 00735000 ffff8000 006d3000 ffff8000 006aa25c ffff8000 fe20: 00735000 ffff8000 006d3030 ffff8000 eb45fe50 ffff8003 006fac68 ffff8000 fe40: 00000006 00000006 fe293ee6 ffff8003 eb45feb0 ffff8003 004f8ee8 ffff8000 fe60: 004f8ed4 ffff8000 00735000 ffff8000 00000000 00000000 00000000 00000000 fe80: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 fea0: 00000000 00000000 00000000 00000000 00000000 00000000 000843d0 ffff8000 fec0: 004f8ed4 ffff8000 00000000 00000000 00000000 00000000 00000000 00000000 fee0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 ff00: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 ff20: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 ff40: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 ff60: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 ff80: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 ffa0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000005 00000000 ffe0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 Call trace: [] unmap_range+0x120/0x580 [] free_hyp_pgds+0xa8/0xe4 [] kvm_arch_init+0x268/0x44c [] kvm_init+0x24/0x260 [] arm_init+0x18/0x24 [] do_one_initcall+0x88/0x1a0 [] kernel_init_freeable+0x148/0x1e8 [] kernel_init+0x10/0xd4 Code: 8b000263 92628479 d1000720 eb01001f (f9400340) ---[ end trace 3bc230562e926fa4 ]--- Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Christoffer Dall Cc: Jungseok Lee Cc: Marc Zyngier Acked-by: Marc Zyngier Acked-by: Christoffer Dall --- arch/arm/kvm/mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index 57a403a..79d3fbf 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -197,7 +197,8 @@ static void unmap_range(struct kvm *kvm, pgd_t *pgdp, pgd = pgdp + pgd_index(addr); do { next = kvm_pgd_addr_end(addr, end); - unmap_puds(kvm, pgd, addr, next); + if (!pgd_none(*pgd)) + unmap_puds(kvm, pgd, addr, next); } while (pgd++, addr = next, addr != end); }