xen/x86: prevent PVH type from getting clobbered

stable inclusion
from stable-5.10.76
commit 101e1bcb114743033f0df86adcaa9b8571f93a06
bugzilla: 182988 https://gitee.com/openeuler/kernel/issues/I4IAHF

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=101e1bcb114743033f0df86adcaa9b8571f93a06



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[ Upstream commit 9172b5c4 ]

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 <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>

Link: https://lore.kernel.org/r/d301677b-6f22-5ae6-bd36-458e1f323d0b@suse.com


Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>