From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752401AbcFVCf5 (ORCPT ); Tue, 21 Jun 2016 22:35:57 -0400 Received: from smtp-fw-33001.amazon.com ([207.171.189.228]:17933 "EHLO smtp-fw-33001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751746AbcFVCfz (ORCPT ); Tue, 21 Jun 2016 22:35:55 -0400 X-IronPort-AV: E=Sophos;i="5.26,508,1459814400"; d="scan'208";a="518547120" From: KarimAllah Ahmed To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org Cc: KarimAllah Ahmed , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Borislav Petkov , Denys Vlasenko , Andrew Morton , Toshi Kani , Tony Luck Subject: [PATCH] kvm, x86: Properly check whether a pfn is an MMIO or not Date: Wed, 22 Jun 2016 04:34:26 +0200 Message-Id: <1466562866-31524-1-git-send-email-karahmed@amazon.de> X-Mailer: git-send-email 2.8.2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org pfn_valid check is not sufficient because it only checks if a page has a struct page or not, if for example "mem=" was passed to the kernel some valid pages won't have a struct page. This means that if guests were assigned valid memory that lies after the mem= boundary it will be passed uncached to the guest no matter what the guest caching attributes are for this memory. Use the original e820 map to check whether a certain pfn belongs to RAM or not. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: H. Peter Anvin Cc: Paolo Bonzini Cc: Radim Krčmář Cc: Borislav Petkov Cc: Denys Vlasenko Cc: Andrew Morton Cc: Toshi Kani Cc: Tony Luck Cc: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org Cc: x86@kernel.org Signed-off-by: KarimAllah Ahmed --- arch/x86/include/asm/e820.h | 1 + arch/x86/kernel/e820.c | 18 ++++++++++++++++++ arch/x86/kvm/mmu.c | 2 +- 3 files changed, 20 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/e820.h b/arch/x86/include/asm/e820.h index 3ab0537..2d4f7d8 100644 --- a/arch/x86/include/asm/e820.h +++ b/arch/x86/include/asm/e820.h @@ -16,6 +16,7 @@ extern struct e820map e820_saved; extern unsigned long pci_mem_start; extern int e820_any_mapped(u64 start, u64 end, unsigned type); extern int e820_all_mapped(u64 start, u64 end, unsigned type); +extern bool e820_is_ram(u64 addr); extern void e820_add_region(u64 start, u64 size, int type); extern void e820_print_map(char *who); extern int diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 621b501..387cdba 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -105,6 +105,24 @@ int __init e820_all_mapped(u64 start, u64 end, unsigned type) return 0; } +bool +e820_is_ram(u64 addr) +{ + int i; + + for (i = 0; i < e820_saved.nr_map; i++) { + struct e820entry *ei = &e820_saved.map[i]; + + if (ei->type != E820_RAM) + continue; + if ((addr >= ei->addr) && (addr < (ei->addr + ei->size))) + return true; + } + + return false; +} +EXPORT_SYMBOL_GPL(e820_is_ram); + /* * Add a memory region to the kernel e820 map. */ diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 24e8001..5e07bf5 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2507,7 +2507,7 @@ static bool kvm_is_mmio_pfn(kvm_pfn_t pfn) if (pfn_valid(pfn)) return !is_zero_pfn(pfn) && PageReserved(pfn_to_page(pfn)); - return true; + return !e820_is_ram(pfn << PAGE_SHIFT); } static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep, -- 2.8.2