From: Juergen Gross <jgross@suse.com>
Date: Fri, 28 Jul 2017 12:23:14 +0200
Git-commit: 4ca83dcf4e3bc0c98836dbb97553792ca7ea5429
Patch-mainline: v4.13-rc5
References: bnc#1071891
Subject: xen: fix hvm guest with kaslr enabled
A Xen HVM guest running with KASLR enabled will die rather soon today
because the shared info page mapping is using va() too early. This was
introduced by commit a5d5f328b0e2baa5ee7c119fd66324eb79eeeb66 ("xen:
allocate page for shared info page from low memory").
In order to fix this use early_memremap() to get a temporary virtual
address for shared info until va() can be used safely.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/xen/enlighten_hvm.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index d23531f..de503c2 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -12,6 +12,7 @@
#include <asm/setup.h>
#include <asm/hypervisor.h>
#include <asm/e820/api.h>
+#include <asm/early_ioremap.h>
#include <asm/xen/cpuid.h>
#include <asm/xen/hypervisor.h>
@@ -21,6 +22,8 @@
#include "mmu.h"
#include "smp.h"
+static unsigned long shared_info_pfn;
+
void xen_hvm_init_shared_info(void)
{
struct xen_add_to_physmap xatp;
@@ -28,7 +31,7 @@ void xen_hvm_init_shared_info(void)
xatp.domid = DOMID_SELF;
xatp.idx = 0;
xatp.space = XENMAPSPACE_shared_info;
- xatp.gpfn = virt_to_pfn(HYPERVISOR_shared_info);
+ xatp.gpfn = shared_info_pfn;
if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
BUG();
}
@@ -51,8 +54,16 @@ static void __init reserve_shared_info(void)
pa += PAGE_SIZE)
;
+ shared_info_pfn = PHYS_PFN(pa);
+
memblock_reserve(pa, PAGE_SIZE);
- HYPERVISOR_shared_info = __va(pa);
+ HYPERVISOR_shared_info = early_memremap(pa, PAGE_SIZE);
+}
+
+static void __init xen_hvm_init_mem_mapping(void)
+{
+ early_memunmap(HYPERVISOR_shared_info, PAGE_SIZE);
+ HYPERVISOR_shared_info = __va(PFN_PHYS(shared_info_pfn));
}
static void __init init_hvm_pv_info(void)
@@ -221,5 +232,6 @@ const struct hypervisor_x86 x86_hyper_xen_hvm = {
.init_platform = xen_hvm_guest_init,
.pin_vcpu = xen_pin_vcpu,
.x2apic_available = xen_x2apic_para_available,
+ .init_mem_mapping = xen_hvm_init_mem_mapping,
};
EXPORT_SYMBOL(x86_hyper_xen_hvm);
--
cgit v1.1