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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: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Ankur Arora 2017-06-02 17:05:58 -07:00 committed by Juergen Gross
parent c48f64ab47
commit ad73fd595c
5 changed files with 89 additions and 69 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

101
arch/x86/xen/enlighten.c
View File

@ -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;
@ -137,40 +177,45 @@ 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)];
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.
*/
err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info,
xen_vcpu_nr(cpu), &info);
if (err) {
pr_warn_once("register_vcpu_info failed: cpu=%d err=%d\n",
cpu, err);
xen_have_vcpu_info_placement = 0;
} else {
/*
* 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;
}
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.
*/
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);
xen_have_vcpu_info_placement = 0;
clamp_max_cpus();
} else {
/* This cpu is using the registered vcpu info, even if
later ones fail to. */
per_cpu(xen_vcpu, cpu) = vcpup;
}
}
void xen_reboot(int reason)

6
arch/x86/xen/enlighten_hvm.c
View File

@ -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);
}
}

47
arch/x86/xen/enlighten_pv.c
View File

@ -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();

3
arch/x86/xen/smp_hvm.c
View File

@ -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);

1
arch/x86/xen/xen-ops.h
View File

@ -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