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Commit 4ca83dcf authored by Juergen Gross's avatar Juergen Gross
Browse files

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 a5d5f328 ("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: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent 10231f69

arch/x86/xen/enlighten_hvm.c

+14 −2
Original line number Diff line number Diff line
@@ -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);