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Message-Id: <1496448362-26558-2-git-send-email-ankur.a.arora@oracle.com>
Date: Fri, 2 Jun 2017 17:05:58 -0700
From: Ankur Arora <ankur.a.arora@...cle.com>
To: linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org
Cc: boris.ostrovsky@...cle.com, jgross@...e.com,
Ankur Arora <ankur.a.arora@...cle.com>
Subject: [PATCH 1/5] 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@...cle.com>
Signed-off-by: Ankur Arora <ankur.a.arora@...cle.com>
---
arch/x86/xen/enlighten.c | 101 +++++++++++++++++++++++++++++++------------
arch/x86/xen/enlighten_hvm.c | 6 +--
arch/x86/xen/enlighten_pv.c | 47 +++++---------------
arch/x86/xen/smp_hvm.c | 3 +-
arch/x86/xen/xen-ops.h | 1 +
5 files changed, 89 insertions(+), 69 deletions(-)
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index a5ffcbb20cc0..96b745e3f56c 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -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)
diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c
index a6d014f47e52..eb53da6547ee 100644
--- a/arch/x86/xen/enlighten_hvm.c
+++ b/arch/x86/xen/enlighten_hvm.c
@@ -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);
}
}
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 7cd442690f9d..f51e48299692 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -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);
@@ -1339,9 +1310,17 @@ 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));
@@ -1438,9 +1417,7 @@ 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();
diff --git a/arch/x86/xen/smp_hvm.c b/arch/x86/xen/smp_hvm.c
index f18561bbf5c9..9e0fb9a015d4 100644
--- a/arch/x86/xen/smp_hvm.c
+++ b/arch/x86/xen/smp_hvm.c
@@ -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);
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 9a440a42c618..90828256248b 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -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
--
2.7.4
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