[PATCH AUTOSEL 5.14 06/17] xen/x86: prevent PVH type from getting clobbered
From: Sasha Levin <sashal@kernel.org>
Date: 2021-10-13 00:55:01
Also in:
lkml, xen-devel
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), xen hypervisor x86 · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Juergen Gross
From: Jan Beulich <redacted>
[ Upstream commit 9172b5c4a778da1f855b2e3780b1afabb3cfd523 ]
Like xen_start_flags, xen_domain_type gets set before .bss gets cleared.
Hence this variable also needs to be prevented from getting put in .bss,
which is possible because XEN_NATIVE is an enumerator evaluating to
zero. Any use prior to init_hvm_pv_info() setting the variable again
would lead to wrong decisions; one such case is xenboot_console_setup()
when called as a result of "earlyprintk=xen".
Use __ro_after_init as more applicable than either __section(".data") or
__read_mostly.
Signed-off-by: Jan Beulich <redacted>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/d301677b-6f22-5ae6-bd36-458e1f323d0b@suse.com (local)
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/xen/enlighten.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index c79bd0af2e8c..f252faf5028f 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c@@ -52,9 +52,6 @@ DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); DEFINE_PER_CPU(uint32_t, xen_vcpu_id); EXPORT_PER_CPU_SYMBOL(xen_vcpu_id); -enum xen_domain_type xen_domain_type = XEN_NATIVE; -EXPORT_SYMBOL_GPL(xen_domain_type); - unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START; EXPORT_SYMBOL(machine_to_phys_mapping); unsigned long machine_to_phys_nr;
@@ -69,9 +66,11 @@ __read_mostly int xen_have_vector_callback; EXPORT_SYMBOL_GPL(xen_have_vector_callback); /* - * NB: needs to live in .data because it's used by xen_prepare_pvh which runs - * before clearing the bss. + * NB: These need to live in .data or alike because they're used by + * xen_prepare_pvh() which runs before clearing the bss. */ +enum xen_domain_type __ro_after_init xen_domain_type = XEN_NATIVE; +EXPORT_SYMBOL_GPL(xen_domain_type); uint32_t xen_start_flags __section(".data") = 0; EXPORT_SYMBOL(xen_start_flags);
--
2.33.0