From patchwork Mon Oct 16 20:23:57 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 826498 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3yG8xn4nrgz9s7p for ; Tue, 17 Oct 2017 07:27:09 +1100 (AEDT) Received: from localhost ([::1]:35077 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e4Byd-0004Nd-Py for incoming@patchwork.ozlabs.org; Mon, 16 Oct 2017 16:27:07 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46584) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e4Bvn-0002Ag-21 for qemu-devel@nongnu.org; Mon, 16 Oct 2017 16:24:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e4Bvj-0004YH-J2 for qemu-devel@nongnu.org; Mon, 16 Oct 2017 16:24:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:10275) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e4Bvj-0004Xm-AZ; Mon, 16 Oct 2017 16:24:07 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5C0E1624DE; Mon, 16 Oct 2017 20:24:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 5C0E1624DE Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=david@redhat.com Received: from t460s.redhat.com (ovpn-116-93.ams2.redhat.com [10.36.116.93]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7804D6062D; Mon, 16 Oct 2017 20:24:01 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Date: Mon, 16 Oct 2017 22:23:57 +0200 Message-Id: <20171016202358.3633-2-david@redhat.com> In-Reply-To: <20171016202358.3633-1-david@redhat.com> References: <20171016202358.3633-1-david@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Mon, 16 Oct 2017 20:24:06 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v1 1/2] accel/tcg: allow to invalidate a write TLB entry immediately X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Thomas Huth , David Hildenbrand , cohuck@redhat.com, Alexander Graf , qemu-s390x@nongnu.org, Richard Henderson Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Background: s390x implements Low-Address Protection (LAP). If LAP is enabled, writing to effective addresses (before any transaltion) 0-511 and 4096-4607 triggers a protection exception. So we have subpage protection on the first two pages of every address space (where the lowcore - the CPU private data resides). By immediately invalidating the write entry but allowing the caller to continue, we force every write access onto these first two pages into the slow path. we will get a tlb fault with the specific accessed addresses and can then evaluate if protection applies or not. We have to make sure to ignore the invalid bit if tlb_fill() succeeds. Signed-off-by: David Hildenbrand --- accel/tcg/cputlb.c | 5 ++++- accel/tcg/softmmu_template.h | 4 ++-- include/exec/cpu-all.h | 3 +++ 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index 5b1ef1442c..a23919c3a8 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -694,6 +694,9 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr, } else { tn.addr_write = address; } + if (prot & PAGE_WRITE_INV) { + tn.addr_write |= TLB_INVALID_MASK; + } } /* Pairs with flag setting in tlb_reset_dirty_range */ @@ -978,7 +981,7 @@ static void *atomic_mmu_lookup(CPUArchState *env, target_ulong addr, if (!VICTIM_TLB_HIT(addr_write, addr)) { tlb_fill(ENV_GET_CPU(env), addr, MMU_DATA_STORE, mmu_idx, retaddr); } - tlb_addr = tlbe->addr_write; + tlb_addr = tlbe->addr_write & ~TLB_INVALID_MASK; } /* Check notdirty */ diff --git a/accel/tcg/softmmu_template.h b/accel/tcg/softmmu_template.h index d7563292a5..3fc5144316 100644 --- a/accel/tcg/softmmu_template.h +++ b/accel/tcg/softmmu_template.h @@ -285,7 +285,7 @@ void helper_le_st_name(CPUArchState *env, target_ulong addr, DATA_TYPE val, if (!VICTIM_TLB_HIT(addr_write, addr)) { tlb_fill(ENV_GET_CPU(env), addr, MMU_DATA_STORE, mmu_idx, retaddr); } - tlb_addr = env->tlb_table[mmu_idx][index].addr_write; + tlb_addr = env->tlb_table[mmu_idx][index].addr_write & ~TLB_INVALID_MASK; } /* Handle an IO access. */ @@ -361,7 +361,7 @@ void helper_be_st_name(CPUArchState *env, target_ulong addr, DATA_TYPE val, if (!VICTIM_TLB_HIT(addr_write, addr)) { tlb_fill(ENV_GET_CPU(env), addr, MMU_DATA_STORE, mmu_idx, retaddr); } - tlb_addr = env->tlb_table[mmu_idx][index].addr_write; + tlb_addr = env->tlb_table[mmu_idx][index].addr_write & ~TLB_INVALID_MASK; } /* Handle an IO access. */ diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h index 778031c3d7..0b141683f0 100644 --- a/include/exec/cpu-all.h +++ b/include/exec/cpu-all.h @@ -245,6 +245,9 @@ extern intptr_t qemu_host_page_mask; /* original state of the write flag (used when tracking self-modifying code */ #define PAGE_WRITE_ORG 0x0010 +/* Invalidate the TLB entry immediately, helpful for s390x + * Low-Address-Protection. Used with PAGE_WRITE in tlb_set_page_with_attrs() */ +#define PAGE_WRITE_INV 0x0040 #if defined(CONFIG_BSD) && defined(CONFIG_USER_ONLY) /* FIXME: Code that sets/uses this is broken and needs to go away. */ #define PAGE_RESERVED 0x0020