The new context tracking subsystem unconditionally includes kvm_host.h headers for the guest enter/exit macros. This causes a compile failure when KVM is not enabled.
Fix by adding an IS_ENABLED(CONFIG_KVM) check to kvm_host so it can be included/compiled even when KVM is not enabled.
Cc: Frederic Weisbecker fweisbec@gmail.com Signed-off-by: Kevin Hilman khilman@linaro.org --- Applies on v3.9-rc2
include/linux/kvm_host.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index cad77fe..a942863 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1,6 +1,8 @@ #ifndef __KVM_HOST_H #define __KVM_HOST_H
+#if IS_ENABLED(CONFIG_KVM) + /* * This work is licensed under the terms of the GNU GPL, version 2. See * the COPYING file in the top-level directory. @@ -1055,5 +1057,8 @@ static inline bool kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu *vcpu) }
#endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */ +#else +static inline void __guest_enter(void) { return; } +static inline void __guest_exit(void) { return; } +#endif /* IS_ENABLED(CONFIG_KVM) */ #endif -
On 03/14/2013 07:13:46 PM, Kevin Hilman wrote:
This broke the PPC non-KVM build, which was relying on stub functions in kvm_ppc.h, which relies on "struct vcpu" in kvm_host.h.
Why can't the entirety kvm_host.h be included regardless of CONFIG_KVM, just like most other feature-specific headers? Why can't the if/else just go around the functions that you want to stub out for non-KVM builds?
-Scott
Gleb Natapov gleb@redhat.com writes:
Not specficially ARM related, but more context tracking related since kernel/context_tracking.c pulls in kvm_host.h, which attempts to pull in <asm/kvm*.h> which may not exist on some platforms.
At least for ARM, KVM support was added in v3.9 so this patch can probably be dropped since the non-KVM builds on ARM now work. But any platform without the <asm/kvm*.h> will still be broken when trying to build the context tracker.
Kevin
Gleb Natapov gleb@redhat.com writes:
I proposed something like that in an earlier version but Frederic asked me to propose a fix to the KVM headers instead.
Just in case fixing the context tracking subsystem is preferred, the patch below fixes the problem also.
Kevin
From f22995a262144d0d61705fa72134694d911283eb Mon Sep 17 00:00:00 2001
From: Kevin Hilman khilman@linaro.org Date: Thu, 21 Mar 2013 16:57:14 -0700 Subject: [PATCH] context_tracking: fix !CONFIG_KVM compile: add stub guest enter/exit
When KVM is not enabled, or not available on a platform, the KVM headers should not be included. Instead, just define stub __guest_[enter|exit] functions.
Cc: Frederic Weisbecker fweisbec@gmail.com Signed-off-by: Kevin Hilman khilman@linaro.org --- kernel/context_tracking.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 65349f0..64b0f80 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -15,12 +15,18 @@ */
#include <linux/context_tracking.h> -#include <linux/kvm_host.h> #include <linux/rcupdate.h> #include <linux/sched.h> #include <linux/hardirq.h> #include <linux/export.h>
+#if IS_ENABLED(CONFIG_KVM) +#include <linux/kvm_host.h> +#else +#define __guest_enter() +#define __guest_exit() +#endif + DEFINE_PER_CPU(struct context_tracking, context_tracking) = { #ifdef CONFIG_CONTEXT_TRACKING_FORCE .active = true,
2013/3/21 Gleb Natapov gleb@redhat.com:
Isn't is simpler for kernel/context_tracking.c to define empty __guest_enter()/__guest_exit() if !CONFIG_KVM.
That doesn't look right. Off-cases are usually handled from the headers, right? So that we avoid iffdeffery ugliness in core code.
Gleb Natapov gleb@redhat.com writes:
Here's a version to do that.
Kevin
From d9d909394479dd7ff90b7bddb95a564945406719 Mon Sep 17 00:00:00 2001
From: Kevin Hilman khilman@linaro.org Date: Mon, 25 Mar 2013 14:12:41 -0700 Subject: [PATCH v2] ontext_tracking: fix !CONFIG_KVM compile: add stub guest enter/exit
When KVM is not enabled, or not available on a platform, the KVM headers should not be included. Instead, just define stub __guest_[enter|exit] functions.
Cc: Frederic Weisbecker fweisbec@gmail.com Signed-off-by: Kevin Hilman khilman@linaro.org --- include/linux/context_tracking.h | 7 +++++++ kernel/context_tracking.c | 1 - 2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h index 365f4a6..9d0f242 100644 --- a/include/linux/context_tracking.h +++ b/include/linux/context_tracking.h @@ -3,6 +3,13 @@
#include <linux/sched.h> #include <linux/percpu.h> +#if IS_ENABLED(CONFIG_KVM) +#include <linux/kvm_host.h> +#else +#define __guest_enter() +#define __guest_exit() +#endif + #include <asm/ptrace.h>
struct context_tracking { diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 65349f0..85bdde1 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -15,7 +15,6 @@ */
#include <linux/context_tracking.h> -#include <linux/kvm_host.h> #include <linux/rcupdate.h> #include <linux/sched.h> #include <linux/hardirq.h>
On Mon, Mar 25, 2013 at 02:14:20PM -0700, Kevin Hilman wrote:
Sorry for my very delayed response...
May be it would be cleaner to move guest_enter/exit definitions altogether in linux/context_tracking.h
After all that's where the implementation mostly belong to.
Let me see if I can get that in shape.
Thanks.
On Thu, May 16, 2013 at 12:52:03AM +0200, Frederic Weisbecker wrote:
Does the following work for you?
--- commit b1633c075527653a99df6fd54d2611cf8c8047f5 Author: Frederic Weisbecker fweisbec@gmail.com Date: Thu May 16 01:21:38 2013 +0200
kvm: Move guest entry/exit APIs to context_tracking
Signed-off-by: Frederic Weisbecker fweisbec@gmail.com
diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h index 365f4a6..fc09d7b 100644 --- a/include/linux/context_tracking.h +++ b/include/linux/context_tracking.h @@ -3,6 +3,7 @@
#include <linux/sched.h> #include <linux/percpu.h> +#include <linux/vtime.h> #include <asm/ptrace.h>
struct context_tracking { @@ -19,6 +20,26 @@ struct context_tracking { } state; };
+static inline void __guest_enter(void) +{ + /* + * This is running in ioctl context so we can avoid + * the call to vtime_account() with its unnecessary idle check. + */ + vtime_account_system(current); + current->flags |= PF_VCPU; +} + +static inline void __guest_exit(void) +{ + /* + * This is running in ioctl context so we can avoid + * the call to vtime_account() with its unnecessary idle check. + */ + vtime_account_system(current); + current->flags &= ~PF_VCPU; +} + #ifdef CONFIG_CONTEXT_TRACKING DECLARE_PER_CPU(struct context_tracking, context_tracking);
@@ -35,6 +56,9 @@ static inline bool context_tracking_active(void) extern void user_enter(void); extern void user_exit(void);
+extern void guest_enter(void); +extern void guest_exit(void); + static inline enum ctx_state exception_enter(void) { enum ctx_state prev_ctx; @@ -57,6 +81,17 @@ extern void context_tracking_task_switch(struct task_struct *prev, static inline bool context_tracking_in_user(void) { return false; } static inline void user_enter(void) { } static inline void user_exit(void) { } + +static inline void guest_enter(void) +{ + __guest_enter(); +} + +static inline void guest_exit(void) +{ + __guest_exit(); +} + static inline enum ctx_state exception_enter(void) { return 0; } static inline void exception_exit(enum ctx_state prev_ctx) { } static inline void context_tracking_task_switch(struct task_struct *prev, diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index f0eea07..8db53cf 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -23,6 +23,7 @@ #include <linux/ratelimit.h> #include <linux/err.h> #include <linux/irqflags.h> +#include <linux/context_tracking.h> #include <asm/signal.h>
#include <linux/kvm.h> @@ -760,42 +761,6 @@ static inline int kvm_iommu_unmap_guest(struct kvm *kvm) } #endif
-static inline void __guest_enter(void) -{ - /* - * This is running in ioctl context so we can avoid - * the call to vtime_account() with its unnecessary idle check. - */ - vtime_account_system(current); - current->flags |= PF_VCPU; -} - -static inline void __guest_exit(void) -{ - /* - * This is running in ioctl context so we can avoid - * the call to vtime_account() with its unnecessary idle check. - */ - vtime_account_system(current); - current->flags &= ~PF_VCPU; -} - -#ifdef CONFIG_CONTEXT_TRACKING -extern void guest_enter(void); -extern void guest_exit(void); - -#else /* !CONFIG_CONTEXT_TRACKING */ -static inline void guest_enter(void) -{ - __guest_enter(); -} - -static inline void guest_exit(void) -{ - __guest_exit(); -} -#endif /* !CONFIG_CONTEXT_TRACKING */ - static inline void kvm_guest_enter(void) { unsigned long flags;
Frederic Weisbecker fweisbec@gmail.com writes:
Nope.
Since it still includs kvm_host.h on non-KVM builds, there is potential for problems. For example, on ARM (v3.10-rc1 + this patch) has this build error:
CC kernel/context_tracking.o In file included from /work/kernel/linaro/nohz/arch/arm/include/asm/kvm_host.h:41:0, from /work/kernel/linaro/nohz/include/linux/kvm_host.h:34, from /work/kernel/linaro/nohz/kernel/context_tracking.c:18: /work/kernel/linaro/nohz/arch/arm/include/asm/kvm_vgic.h:38:6: warning: "CONFIG_KVM_ARM_MAX_VCPUS" is not defined [-Wundef] In file included from /work/kernel/linaro/nohz/arch/arm/include/asm/kvm_host.h:41:0, from /work/kernel/linaro/nohz/include/linux/kvm_host.h:34, from /work/kernel/linaro/nohz/kernel/context_tracking.c:18: /work/kernel/linaro/nohz/arch/arm/include/asm/kvm_vgic.h:59:11: error: 'CONFIG_KVM_ARM_MAX_VCPUS' undeclared here (not in a function)
Kevin
On Fri, May 17, 2013 at 07:09:42AM -0700, Kevin Hilman wrote:
Sorry I forgot to remove the include to kvm_host.h in context_tracking.c, here's the fixed patch:
diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h index 365f4a6..fc09d7b 100644 --- a/include/linux/context_tracking.h +++ b/include/linux/context_tracking.h @@ -3,6 +3,7 @@
#include <linux/sched.h> #include <linux/percpu.h> +#include <linux/vtime.h> #include <asm/ptrace.h>
struct context_tracking { @@ -19,6 +20,26 @@ struct context_tracking { } state; };
+static inline void __guest_enter(void) +{ + /* + * This is running in ioctl context so we can avoid + * the call to vtime_account() with its unnecessary idle check. + */ + vtime_account_system(current); + current->flags |= PF_VCPU; +} + +static inline void __guest_exit(void) +{ + /* + * This is running in ioctl context so we can avoid + * the call to vtime_account() with its unnecessary idle check. + */ + vtime_account_system(current); + current->flags &= ~PF_VCPU; +} + #ifdef CONFIG_CONTEXT_TRACKING DECLARE_PER_CPU(struct context_tracking, context_tracking);
@@ -35,6 +56,9 @@ static inline bool context_tracking_active(void) extern void user_enter(void); extern void user_exit(void);
+extern void guest_enter(void); +extern void guest_exit(void); + static inline enum ctx_state exception_enter(void) { enum ctx_state prev_ctx; @@ -57,6 +81,17 @@ extern void context_tracking_task_switch(struct task_struct *prev, static inline bool context_tracking_in_user(void) { return false; } static inline void user_enter(void) { } static inline void user_exit(void) { } + +static inline void guest_enter(void) +{ + __guest_enter(); +} + +static inline void guest_exit(void) +{ + __guest_exit(); +} + static inline enum ctx_state exception_enter(void) { return 0; } static inline void exception_exit(enum ctx_state prev_ctx) { } static inline void context_tracking_task_switch(struct task_struct *prev, diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index f0eea07..8db53cf 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -23,6 +23,7 @@ #include <linux/ratelimit.h> #include <linux/err.h> #include <linux/irqflags.h> +#include <linux/context_tracking.h> #include <asm/signal.h>
#include <linux/kvm.h> @@ -760,42 +761,6 @@ static inline int kvm_iommu_unmap_guest(struct kvm *kvm) } #endif
-static inline void __guest_enter(void) -{ - /* - * This is running in ioctl context so we can avoid - * the call to vtime_account() with its unnecessary idle check. - */ - vtime_account_system(current); - current->flags |= PF_VCPU; -} - -static inline void __guest_exit(void) -{ - /* - * This is running in ioctl context so we can avoid - * the call to vtime_account() with its unnecessary idle check. - */ - vtime_account_system(current); - current->flags &= ~PF_VCPU; -} - -#ifdef CONFIG_CONTEXT_TRACKING -extern void guest_enter(void); -extern void guest_exit(void); - -#else /* !CONFIG_CONTEXT_TRACKING */ -static inline void guest_enter(void) -{ - __guest_enter(); -} - -static inline void guest_exit(void) -{ - __guest_exit(); -} -#endif /* !CONFIG_CONTEXT_TRACKING */ - static inline void kvm_guest_enter(void) { unsigned long flags; diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 65349f0..85bdde1 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -15,7 +15,6 @@ */
#include <linux/context_tracking.h> -#include <linux/kvm_host.h> #include <linux/rcupdate.h> #include <linux/sched.h> #include <linux/hardirq.h>
Frederic Weisbecker fweisbec@gmail.com writes:
Yup, that one builds just fine.
Reviewed-and-Tested-by: Kevin Hilman khilman@linaro.org
Kevin
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