On 24.05.21 17:26, Greg Kroah-Hartman wrote:
From: Jan Beulich <jbeulich@xxxxxxxx>
commit ae897fda4f507e4b239f0bdfd578b3688ca96fb4 upstream.
xen_setup_gdt(), via xen_load_gdt_boot(), wants to adjust page tables.
For this to work when NX is not available, x86_configure_nx() needs to
be called first.
[jgross] Note that this is a revert of 36104cb9012a82e73 ("x86/xen:
Delay get_cpu_cap until stack canary is established"), which is possible
now that we no longer support running as PV guest in 32-bit mode.
Cc: <stable.vger.kernel.org> # 5.9
Sorry for messing up the stable link, but please don't include this patch in stable kernels before 5.9 Juergen
Fixes: 36104cb9012a82e73 ("x86/xen: Delay get_cpu_cap until stack canary is established") Reported-by: Olaf Hering <olaf@xxxxxxxxx> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Reviewed-by: Juergen Gross <jgross@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/12a866b0-9e89-59f7-ebeb-a2a6cec0987a@xxxxxxxx Signed-off-by: Juergen Gross <jgross@xxxxxxxx> --- arch/x86/xen/enlighten_pv.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -1246,16 +1246,16 @@ asmlinkage __visible void __init xen_sta /* Get mfn list */ xen_build_dynamic_phys_to_machine();+ /* Work out if we support NX */+ get_cpu_cap(&boot_cpu_data); + x86_configure_nx(); + /* * Set up kernel GDT and segment registers, mainly so that * -fstack-protector code can be executed. */ xen_setup_gdt(0);- /* Work out if we support NX */- get_cpu_cap(&boot_cpu_data); - x86_configure_nx(); - /* Determine virtual and physical address sizes */ get_cpu_address_sizes(&boot_cpu_data);
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