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Commit ad73fd59 authored by Ankur Arora's avatar Ankur Arora Committed by Juergen Gross
Browse files

xen/vcpu: Simplify xen_vcpu related code 



Largely mechanical changes to aid unification of xen_vcpu_restore()
logic for PV, PVH and PVHVM.

xen_vcpu_setup(): the only change in logic is that clamp_max_cpus()
is now handled inside the "if (!xen_have_vcpu_info_placement)" block.

xen_vcpu_restore(): code movement from enlighten_pv.c to enlighten.c.

xen_vcpu_info_reset(): pulls together all the code where xen_vcpu
is set to default.

Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarAnkur Arora <ankur.a.arora@oracle.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
parent c48f64ab

arch/x86/xen/enlighten.c

+73 −28
Original line number Diff line number Diff line
@@ -106,6 +106,35 @@ int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int), 
	return rc >= 0 ? 0 : rc;

}



/*

 * On restore, set the vcpu placement up again.

 * If it fails, then we're in a bad state, since

 * we can't back out from using it...

 */

void xen_vcpu_restore(void)

{

	int cpu;



	for_each_possible_cpu(cpu) {

		bool other_cpu = (cpu != smp_processor_id());

		bool is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, xen_vcpu_nr(cpu),

						NULL);



		if (other_cpu && is_up &&

		    HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL))

			BUG();



		xen_setup_runstate_info(cpu);



		if (xen_have_vcpu_info_placement)

			xen_vcpu_setup(cpu);



		if (other_cpu && is_up &&

		    HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL))

			BUG();

	}

}



static void clamp_max_cpus(void)

{

#ifdef CONFIG_SMP
@@ -114,6 +143,17 @@ static void clamp_max_cpus(void) 
#endif

}



void xen_vcpu_info_reset(int cpu)

{

	if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) {

		per_cpu(xen_vcpu, cpu) =

			&HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];

	} else {

		/* Set to NULL so that if somebody accesses it we get an OOPS */

		per_cpu(xen_vcpu, cpu) = NULL;

	}

}



void xen_vcpu_setup(int cpu)

{

	struct vcpu_register_vcpu_info info;
@@ -137,42 +177,47 @@ void xen_vcpu_setup(int cpu) 
		if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu))

			return;

	}

	if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS)

		per_cpu(xen_vcpu, cpu) =

			&HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];



	if (!xen_have_vcpu_info_placement) {

		if (cpu >= MAX_VIRT_CPUS)

			clamp_max_cpus();

		return;

	}

	xen_vcpu_info_reset(cpu);



	if (xen_have_vcpu_info_placement) {

		vcpup = &per_cpu(xen_vcpu_info, cpu);

		info.mfn = arbitrary_virt_to_mfn(vcpup);

		info.offset = offset_in_page(vcpup);



	/* Check to see if the hypervisor will put the vcpu_info

	   structure where we want it, which allows direct access via

	   a percpu-variable.

	   N.B. This hypercall can _only_ be called once per CPU. Subsequent

	   calls will error out with -EINVAL. This is due to the fact that

	   hypervisor has no unregister variant and this hypercall does not

	   allow to over-write info.mfn and info.offset.

		/*

		 * Check to see if the hypervisor will put the vcpu_info

		 * structure where we want it, which allows direct access via

		 * a percpu-variable.

		 * N.B. This hypercall can _only_ be called once per CPU.

		 * Subsequent calls will error out with -EINVAL. This is due to

		 * the fact that hypervisor has no unregister variant and this

		 * hypercall does not allow to over-write info.mfn and

		 * info.offset.

		 */

	err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu),

				 &info);

		err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info,

					 xen_vcpu_nr(cpu), &info);



		if (err) {

		printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err);

			pr_warn_once("register_vcpu_info failed: cpu=%d err=%d\n",

				     cpu, err);

			xen_have_vcpu_info_placement = 0;

		clamp_max_cpus();

		} else {

		/* This cpu is using the registered vcpu info, even if

		   later ones fail to. */

			/*

			 * This cpu is using the registered vcpu info, even if

			 * later ones fail to.

			 */

			per_cpu(xen_vcpu, cpu) = vcpup;

		}

	}



	if (!xen_have_vcpu_info_placement) {

		if (cpu >= MAX_VIRT_CPUS)

			clamp_max_cpus();

		return;

	}

}



void xen_reboot(int reason)

{

	struct sched_shutdown r = { .reason = reason };

arch/x86/xen/enlighten_hvm.c

+1 −5
Original line number Diff line number Diff line
@@ -45,11 +45,7 @@ void __ref xen_hvm_init_shared_info(void) 
	 * online but xen_hvm_init_shared_info is run at resume time too and

	 * in that case multiple vcpus might be online. */

	for_each_online_cpu(cpu) {

		/* Leave it to be NULL. */

		if (xen_vcpu_nr(cpu) >= MAX_VIRT_CPUS)

			continue;

		per_cpu(xen_vcpu, cpu) =

			&HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];

		xen_vcpu_info_reset(cpu);

	}

}

arch/x86/xen/enlighten_pv.c

+12 −35
Original line number Diff line number Diff line
@@ -107,35 +107,6 @@ struct tls_descs { 
 */

static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);



/*

 * On restore, set the vcpu placement up again.

 * If it fails, then we're in a bad state, since

 * we can't back out from using it...

 */

void xen_vcpu_restore(void)

{

	int cpu;



	for_each_possible_cpu(cpu) {

		bool other_cpu = (cpu != smp_processor_id());

		bool is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, xen_vcpu_nr(cpu),

						NULL);



		if (other_cpu && is_up &&

		    HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL))

			BUG();



		xen_setup_runstate_info(cpu);



		if (xen_have_vcpu_info_placement)

			xen_vcpu_setup(cpu);



		if (other_cpu && is_up &&

		    HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL))

			BUG();

	}

}



static void __init xen_banner(void)

{

	unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
@@ -1332,9 +1303,17 @@ asmlinkage __visible void __init xen_start_kernel(void) 
	 */

	acpi_numa = -1;

#endif

	/* Don't do the full vcpu_info placement stuff until we have a

	   possible map and a non-dummy shared_info. */

	per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];

	/* Let's presume PV guests always boot on vCPU with id 0. */

	per_cpu(xen_vcpu_id, 0) = 0;



	/*

	 * Setup xen_vcpu early because start_kernel needs it for

	 * local_irq_disable(), irqs_disabled().

	 *

	 * Don't do the full vcpu_info placement stuff until we have

	 * the cpu_possible_mask and a non-dummy shared_info.

	 */

	xen_vcpu_info_reset(0);



	WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_pv, xen_cpu_dead_pv));
@@ -1431,9 +1410,7 @@ asmlinkage __visible void __init xen_start_kernel(void) 
#endif

	xen_raw_console_write("about to get started...\n");



	/* Let's presume PV guests always boot on vCPU with id 0. */

	per_cpu(xen_vcpu_id, 0) = 0;



	/* We need this for printk timestamps */

	xen_setup_runstate_info(0);



	xen_efi_init();

arch/x86/xen/smp_hvm.c

+2 −1
Original line number Diff line number Diff line
@@ -12,7 +12,8 @@ static void __init xen_hvm_smp_prepare_boot_cpu(void) 
	native_smp_prepare_boot_cpu();



	/*

	 * Setup vcpu_info for boot CPU.

	 * Setup vcpu_info for boot CPU. Secondary CPUs get their vcpu_info

	 * in xen_cpu_up_prepare_hvm().

	 */

	xen_vcpu_setup(0);

arch/x86/xen/xen-ops.h

+1 −0
Original line number Diff line number Diff line
@@ -79,6 +79,7 @@ bool xen_vcpu_stolen(int vcpu); 
extern int xen_have_vcpu_info_placement;



void xen_vcpu_setup(int cpu);

void xen_vcpu_info_reset(int cpu);

void xen_setup_vcpu_info_placement(void);



#ifdef CONFIG_SMP