x86/xen: Set EFER.NX and EFER.SCE in PVH guests
This fixes two bugs in PVH guests:
- Not setting EFER.NX means the NX bit in page table entries is
ignored on Intel processors and causes reserved bit page faults on
AMD processors.
- After the Xen commit 7645640d6ff1 ("x86/PVH: don't set EFER_SCE for
pvh guest") PVH guests are required to set EFER.SCE to enable the
SYSCALL instruction.
Secondary VCPUs are started with pagetables with the NX bit set so
EFER.NX must be set before using any stack or data segment.
xen_pvh_cpu_early_init() is the new secondary VCPU entry point that
sets EFER before jumping to cpu_bringup_and_idle().
Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index f7e01fa..acb0eff 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1463,6 +1463,7 @@
pv_cpu_ops.load_gdt = xen_load_gdt;
}
+#ifdef CONFIG_XEN_PVH
/*
* A PV guest starts with default flags that are not set for PVH, set them
* here asap.
@@ -1508,12 +1509,15 @@
return;
xen_have_vector_callback = 1;
+
+ xen_pvh_early_cpu_init(0, false);
xen_pvh_set_cr_flags(0);
#ifdef CONFIG_X86_32
BUG(); /* PVH: Implement proper support. */
#endif
}
+#endif /* CONFIG_XEN_PVH */
/* First C function to be called on Xen boot */
asmlinkage __visible void __init xen_start_kernel(void)
@@ -1528,7 +1532,9 @@
xen_domain_type = XEN_PV_DOMAIN;
xen_setup_features();
+#ifdef CONFIG_XEN_PVH
xen_pvh_early_guest_init();
+#endif
xen_setup_machphys_mapping();
/* Install Xen paravirt ops */