From: Ankur Arora <ankur.a.arora@oracle.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: peterz@infradead.org, hpa@zytor.com, jpoimboe@redhat.com,
namit@vmware.com, mhiramat@kernel.org, jgross@suse.com,
bp@alien8.de, vkuznets@redhat.com, pbonzini@redhat.com,
boris.ostrovsky@oracle.com, mihai.carabas@oracle.com,
kvm@vger.kernel.org, xen-devel@lists.xenproject.org,
virtualization@lists.linux-foundation.org,
Ankur Arora <ankur.a.arora@oracle.com>
Subject: [RFC PATCH 20/26] x86/paravirt: Enable pv-spinlocks in runtime_patch()
Date: Tue, 7 Apr 2020 22:03:17 -0700 [thread overview]
Message-ID: <20200408050323.4237-21-ankur.a.arora@oracle.com> (raw)
In-Reply-To: <20200408050323.4237-1-ankur.a.arora@oracle.com>
Enable runtime patching of paravirt spinlocks. These can be trivially
enabled because pv_lock_ops are never preemptible -- preemption is
disabled at entry to spin_lock*().
Note that a particular CPU instance might get preempted in the host but
because runtime_patching() is called via stop_machine(), the migration
thread would flush out any kernel threads preempted in the host.
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
arch/x86/include/asm/paravirt.h | 10 +++++-----
arch/x86/kernel/paravirt_patch.c | 12 ++++++++++++
kernel/locking/lock_events.c | 2 +-
3 files changed, 18 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 694d8daf4983..cb3d0a91c060 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -642,27 +642,27 @@ static inline void __set_fixmap(unsigned /* enum fixed_addresses */ idx,
static __always_inline void pv_queued_spin_lock_slowpath(struct qspinlock *lock,
u32 val)
{
- PVOP_VCALL2(lock.queued_spin_lock_slowpath, lock, val);
+ PVRTOP_VCALL2(lock.queued_spin_lock_slowpath, lock, val);
}
static __always_inline void pv_queued_spin_unlock(struct qspinlock *lock)
{
- PVOP_VCALLEE1(lock.queued_spin_unlock, lock);
+ PVRTOP_VCALLEE1(lock.queued_spin_unlock, lock);
}
static __always_inline void pv_wait(u8 *ptr, u8 val)
{
- PVOP_VCALL2(lock.wait, ptr, val);
+ PVRTOP_VCALL2(lock.wait, ptr, val);
}
static __always_inline void pv_kick(int cpu)
{
- PVOP_VCALL1(lock.kick, cpu);
+ PVRTOP_VCALL1(lock.kick, cpu);
}
static __always_inline bool pv_vcpu_is_preempted(long cpu)
{
- return PVOP_CALLEE1(bool, lock.vcpu_is_preempted, cpu);
+ return PVRTOP_CALLEE1(bool, lock.vcpu_is_preempted, cpu);
}
void __raw_callee_save___native_queued_spin_unlock(struct qspinlock *lock);
diff --git a/arch/x86/kernel/paravirt_patch.c b/arch/x86/kernel/paravirt_patch.c
index 3eb8c0e720b4..3f8606f2811c 100644
--- a/arch/x86/kernel/paravirt_patch.c
+++ b/arch/x86/kernel/paravirt_patch.c
@@ -152,6 +152,18 @@ int runtime_patch(u8 type, void *insn_buff, void *op,
/* Nothing whitelisted for now. */
switch (type) {
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+ /*
+ * Preemption is always disabled in the lifetime of a spinlock
+ * (whether held or while waiting to acquire.)
+ */
+ case PARAVIRT_PATCH(lock.queued_spin_lock_slowpath):
+ case PARAVIRT_PATCH(lock.queued_spin_unlock):
+ case PARAVIRT_PATCH(lock.wait):
+ case PARAVIRT_PATCH(lock.kick):
+ case PARAVIRT_PATCH(lock.vcpu_is_preempted):
+ break;
+#endif
default:
pr_warn("type=%d unsuitable for runtime-patching\n", type);
return -EINVAL;
diff --git a/kernel/locking/lock_events.c b/kernel/locking/lock_events.c
index fa2c2f951c6b..c3057e82e6f9 100644
--- a/kernel/locking/lock_events.c
+++ b/kernel/locking/lock_events.c
@@ -115,7 +115,7 @@ static const struct file_operations fops_lockevent = {
.llseek = default_llseek,
};
-#ifdef CONFIG_PARAVIRT_SPINLOCKS
+#if defined(CONFIG_PARAVIRT_SPINLOCKS) && !defined(CONFIG_PARAVIRT_RUNTIME)
#include <asm/paravirt.h>
static bool __init skip_lockevent(const char *name)
--
2.20.1
next prev parent reply other threads:[~2020-04-08 5:06 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-08 5:02 [RFC PATCH 00/26] Runtime paravirt patching Ankur Arora
2020-04-08 5:02 ` [RFC PATCH 01/26] x86/paravirt: Specify subsection in PVOP macros Ankur Arora
2020-04-08 5:02 ` [RFC PATCH 02/26] x86/paravirt: Allow paravirt patching post-init Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 03/26] x86/paravirt: PVRTOP macros for PARAVIRT_RUNTIME Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 04/26] x86/alternatives: Refactor alternatives_smp_module* Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 05/26] x86/alternatives: Rename alternatives_smp*, smp_alt_module Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 06/26] x86/alternatives: Remove stale symbols Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 07/26] x86/paravirt: Persist .parainstructions.runtime Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 08/26] x86/paravirt: Stash native pv-ops Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 09/26] x86/paravirt: Add runtime_patch() Ankur Arora
2020-04-08 11:05 ` Peter Zijlstra
2020-04-08 5:03 ` [RFC PATCH 10/26] x86/paravirt: Add primitives to stage pv-ops Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 11/26] x86/alternatives: Remove return value of text_poke*() Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 12/26] x86/alternatives: Use __get_unlocked_pte() in text_poke() Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 13/26] x86/alternatives: Split __text_poke() Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 14/26] x86/alternatives: Handle native insns in text_poke_loc*() Ankur Arora
2020-04-08 11:11 ` Peter Zijlstra
2020-04-08 11:17 ` Peter Zijlstra
2020-04-08 5:03 ` [RFC PATCH 15/26] x86/alternatives: Non-emulated text poking Ankur Arora
2020-04-08 11:13 ` Peter Zijlstra
2020-04-08 11:23 ` Peter Zijlstra
2020-04-08 5:03 ` [RFC PATCH 16/26] x86/alternatives: Add paravirt patching at runtime Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 17/26] x86/alternatives: Add patching logic in text_poke_site() Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 18/26] x86/alternatives: Handle BP in non-emulated text poking Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 19/26] x86/alternatives: NMI safe runtime patching Ankur Arora
2020-04-08 11:36 ` Peter Zijlstra
2020-04-08 5:03 ` Ankur Arora [this message]
2020-04-08 5:03 ` [RFC PATCH 21/26] x86/alternatives: Paravirt runtime selftest Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 22/26] kvm/paravirt: Encapsulate KVM pv switching logic Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 23/26] x86/kvm: Add worker to trigger runtime patching Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 24/26] x86/kvm: Support dynamic CPUID hints Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 25/26] x86/kvm: Guest support for dynamic hints Ankur Arora
2020-04-08 5:03 ` [RFC PATCH 26/26] x86/kvm: Add hint change notifier for KVM_HINT_REALTIME Ankur Arora
2020-04-08 12:08 ` [RFC PATCH 00/26] Runtime paravirt patching Peter Zijlstra
2020-04-08 13:33 ` Jürgen Groß
2020-04-08 14:49 ` Peter Zijlstra
2020-04-10 9:18 ` Ankur Arora
2020-04-08 12:28 ` Jürgen Groß
2020-04-10 7:56 ` Ankur Arora
2020-04-10 9:32 ` Ankur Arora
2020-04-08 14:12 ` Thomas Gleixner
2020-04-10 9:55 ` Ankur Arora
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