linux-kernel - [PATCH 10/14] KVM: x86/mmu: Remove obsolete gfn restoration in FNAME(fetch)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed,  8 Jan 2020 12:24:44 -0800
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Paul Mackerras <paulus@...abs.org>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        kvm-ppc@...r.kernel.org, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        syzbot+c9d1fb51ac9d0d10c39d@...kaller.appspotmail.com,
        Andrea Arcangeli <aarcange@...hat.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Barret Rhoden <brho@...gle.com>,
        David Hildenbrand <david@...hat.com>,
        Jason Zeng <jason.zeng@...el.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Liran Alon <liran.alon@...cle.com>,
        linux-nvdimm <linux-nvdimm@...ts.01.org>
Subject: [PATCH 10/14] KVM: x86/mmu: Remove obsolete gfn restoration in FNAME(fetch)

Remove logic to retrieve the original gfn now that HugeTLB mappings are
are identified in FNAME(fetch), i.e. FNAME(page_fault) no longer adjusts
the level or gfn.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/mmu/paging_tmpl.h | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 841506a55815..0560982eda8b 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -621,7 +621,7 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gpa_t addr,
 	struct kvm_shadow_walk_iterator it;
 	unsigned direct_access, access = gw->pt_access;
 	int top_level, hlevel, ret;
-	gfn_t gfn, base_gfn;
+	gfn_t base_gfn = gw->gfn;
 
 	direct_access = gw->pte_access;
 
@@ -666,13 +666,6 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gpa_t addr,
 			link_shadow_page(vcpu, it.sptep, sp);
 	}
 
-	/*
-	 * FNAME(page_fault) might have clobbered the bottom bits of
-	 * gw->gfn, restore them from the virtual address.
-	 */
-	gfn = gw->gfn | ((addr & PT_LVL_OFFSET_MASK(gw->level)) >> PAGE_SHIFT);
-	base_gfn = gfn;
-
 	hlevel = kvm_mmu_hugepage_adjust(vcpu, gw->gfn, max_level, &pfn);
 
 	trace_kvm_mmu_spte_requested(addr, gw->level, pfn);
@@ -684,9 +677,9 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, gpa_t addr,
 		 * We cannot overwrite existing page tables with an NX
 		 * large page, as the leaf could be executable.
 		 */
-		disallowed_hugepage_adjust(it, gfn, &pfn, &hlevel);
+		disallowed_hugepage_adjust(it, gw->gfn, &pfn, &hlevel);
 
-		base_gfn = gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
+		base_gfn = gw->gfn & ~(KVM_PAGES_PER_HPAGE(it.level) - 1);
 		if (it.level == hlevel)
 			break;
 
-- 
2.24.1