xen/pv: Fix OOPS on restore for a PV, !SMP domain (0e4d5837) · Commits · 戴 / test

If CONFIG_SMP is disabled, xen_setup_vcpu_info_placement() is called from xen_setup_shared_info(). This is fine as far as boot goes, but it means that we also call it in the restore path. This results in an OOPS because we assign to pv_mmu_ops.read_cr2 which is __ro_after_init. Also, though less problematically, this means we call xen_vcpu_setup() twice at restore -- once from the vcpu info placement call and the second time from xen_vcpu_restore(). Fix by calling xen_setup_vcpu_info_placement() at boot only. Reviewed-by:

Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by:

Ankur Arora <ankur.a.arora@oracle.com> Signed-off-by:

Juergen Gross <jgross@suse.com>

arch/x86/xen/enlighten_pv.c

+15 −11

Original line number	Diff line number	Diff line
		@@ -931,23 +931,27 @@ void xen_setup_shared_info(void)
		HYPERVISOR_shared_info =
		(struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);

		xen_setup_mfn_list_list();

		if (system_state == SYSTEM_BOOTING) {
		#ifndef CONFIG_SMP
		/* In UP this is as good a place as any to set up shared info */
		/*
		* In UP this is as good a place as any to set up shared info.
		* Limit this to boot only, at restore vcpu setup is done via
		* xen_vcpu_restore().
		*/
		xen_setup_vcpu_info_placement();
		#endif

		xen_setup_mfn_list_list();

		/*
		* Now that shared info is set up we can start using routines that
		* point to pvclock area.
		* Now that shared info is set up we can start using routines
		* that point to pvclock area.
		*/
		if (system_state == SYSTEM_BOOTING)
		xen_init_time_ops();
		}
		}

		/* This is called once we have the cpu_possible_mask */
		void xen_setup_vcpu_info_placement(void)
		void __ref xen_setup_vcpu_info_placement(void)
		{
		int cpu;

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