linux-kernel - [PATCH 1/4] x86/xen: remove 32-bit pv leftovers

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:   Thu, 28 Oct 2021 10:12:18 +0200
From:   Juergen Gross <jgross@...e.com>
To:     xen-devel@...ts.xenproject.org, x86@...nel.org,
        linux-kernel@...r.kernel.org
Cc:     Juergen Gross <jgross@...e.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH 1/4] x86/xen: remove 32-bit pv leftovers

There are some remaining 32-bit pv-guest support leftovers in the Xen
hypercall interface. Remove them.

Signed-off-by: Juergen Gross <jgross@...e.com>
---
 arch/x86/include/asm/xen/hypercall.h | 40 +++++++---------------------
 drivers/xen/mem-reservation.c        | 27 +++++++------------
 2 files changed, 19 insertions(+), 48 deletions(-)

diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
index 454b20815f35..02156b76aa92 100644
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -323,9 +323,7 @@ HYPERVISOR_get_debugreg(int reg)
 static inline int
 HYPERVISOR_update_descriptor(u64 ma, u64 desc)
 {
-	if (sizeof(u64) == sizeof(long))
-		return _hypercall2(int, update_descriptor, ma, desc);
-	return _hypercall4(int, update_descriptor, ma, ma>>32, desc, desc>>32);
+	return _hypercall2(int, update_descriptor, ma, desc);
 }
 
 static inline long
@@ -344,12 +342,7 @@ static inline int
 HYPERVISOR_update_va_mapping(unsigned long va, pte_t new_val,
 			     unsigned long flags)
 {
-	if (sizeof(new_val) == sizeof(long))
-		return _hypercall3(int, update_va_mapping, va,
-				   new_val.pte, flags);
-	else
-		return _hypercall4(int, update_va_mapping, va,
-				   new_val.pte, new_val.pte >> 32, flags);
+	return _hypercall3(int, update_va_mapping, va, new_val.pte, flags);
 }
 
 static inline int
@@ -461,16 +454,10 @@ MULTI_update_va_mapping(struct multicall_entry *mcl, unsigned long va,
 {
 	mcl->op = __HYPERVISOR_update_va_mapping;
 	mcl->args[0] = va;
-	if (sizeof(new_val) == sizeof(long)) {
-		mcl->args[1] = new_val.pte;
-		mcl->args[2] = flags;
-	} else {
-		mcl->args[1] = new_val.pte;
-		mcl->args[2] = new_val.pte >> 32;
-		mcl->args[3] = flags;
-	}
+	mcl->args[1] = new_val.pte;
+	mcl->args[2] = flags;
 
-	trace_xen_mc_entry(mcl, sizeof(new_val) == sizeof(long) ? 3 : 4);
+	trace_xen_mc_entry(mcl, 3);
 }
 
 static inline void
@@ -478,19 +465,10 @@ MULTI_update_descriptor(struct multicall_entry *mcl, u64 maddr,
 			struct desc_struct desc)
 {
 	mcl->op = __HYPERVISOR_update_descriptor;
-	if (sizeof(maddr) == sizeof(long)) {
-		mcl->args[0] = maddr;
-		mcl->args[1] = *(unsigned long *)&desc;
-	} else {
-		u32 *p = (u32 *)&desc;
-
-		mcl->args[0] = maddr;
-		mcl->args[1] = maddr >> 32;
-		mcl->args[2] = *p++;
-		mcl->args[3] = *p;
-	}
-
-	trace_xen_mc_entry(mcl, sizeof(maddr) == sizeof(long) ? 2 : 4);
+	mcl->args[0] = maddr;
+	mcl->args[1] = *(unsigned long *)&desc;
+
+	trace_xen_mc_entry(mcl, 2);
 }
 
 static inline void
diff --git a/drivers/xen/mem-reservation.c b/drivers/xen/mem-reservation.c
index 3782cf070338..24648836e0d4 100644
--- a/drivers/xen/mem-reservation.c
+++ b/drivers/xen/mem-reservation.c
@@ -35,6 +35,7 @@ void __xenmem_reservation_va_mapping_update(unsigned long count,
 	for (i = 0; i < count; i++) {
 		struct page *page = pages[i];
 		unsigned long pfn = page_to_pfn(page);
+		int ret;
 
 		BUG_ON(!page);
 
@@ -46,16 +47,10 @@ void __xenmem_reservation_va_mapping_update(unsigned long count,
 
 		set_phys_to_machine(pfn, frames[i]);
 
-		/* Link back into the page tables if not highmem. */
-		if (!PageHighMem(page)) {
-			int ret;
-
-			ret = HYPERVISOR_update_va_mapping(
-					(unsigned long)__va(pfn << PAGE_SHIFT),
-					mfn_pte(frames[i], PAGE_KERNEL),
-					0);
-			BUG_ON(ret);
-		}
+		ret = HYPERVISOR_update_va_mapping(
+				(unsigned long)__va(pfn << PAGE_SHIFT),
+				mfn_pte(frames[i], PAGE_KERNEL), 0);
+		BUG_ON(ret);
 	}
 }
 EXPORT_SYMBOL_GPL(__xenmem_reservation_va_mapping_update);
@@ -68,6 +63,7 @@ void __xenmem_reservation_va_mapping_reset(unsigned long count,
 	for (i = 0; i < count; i++) {
 		struct page *page = pages[i];
 		unsigned long pfn = page_to_pfn(page);
+		int ret;
 
 		/*
 		 * We don't support PV MMU when Linux and Xen are using
@@ -75,14 +71,11 @@ void __xenmem_reservation_va_mapping_reset(unsigned long count,
 		 */
 		BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE);
 
-		if (!PageHighMem(page)) {
-			int ret;
+		ret = HYPERVISOR_update_va_mapping(
+				(unsigned long)__va(pfn << PAGE_SHIFT),
+				__pte_ma(0), 0);
+		BUG_ON(ret);
 
-			ret = HYPERVISOR_update_va_mapping(
-					(unsigned long)__va(pfn << PAGE_SHIFT),
-					__pte_ma(0), 0);
-			BUG_ON(ret);
-		}
 		__set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
 	}
 }
-- 
2.26.2