Re: [PATCH v4 07/15] x86/paravirt: switch time pvops functions to use static_call()
From: Borislav Petkov <bp@alien8.de>
Date: 2021-02-01 19:54:22
Also in:
kvm, linux-hyperv, lkml, xen-devel
On Wed, Jan 20, 2021 at 02:55:47PM +0100, Juergen Gross wrote:
quoted hunk ↗ jump to hunk
The time pvops functions are the only ones left which might be used in 32-bit mode and which return a 64-bit value. Switch them to use the static_call() mechanism instead of pvops, as this allows quite some simplification of the pvops implementation. Signed-off-by: Juergen Gross <jgross@suse.com> --- V4: - drop paravirt_time.h again - don't move Hyper-V code (Michael Kelley) --- arch/x86/Kconfig | 1 + arch/x86/include/asm/mshyperv.h | 2 +- arch/x86/include/asm/paravirt.h | 17 ++++++++++++++--- arch/x86/include/asm/paravirt_types.h | 6 ------ arch/x86/kernel/cpu/vmware.c | 5 +++-- arch/x86/kernel/kvm.c | 2 +- arch/x86/kernel/kvmclock.c | 2 +- arch/x86/kernel/paravirt.c | 16 ++++++++++++---- arch/x86/kernel/tsc.c | 2 +- arch/x86/xen/time.c | 11 ++++------- drivers/clocksource/hyperv_timer.c | 5 +++-- drivers/xen/time.c | 2 +- 12 files changed, 42 insertions(+), 29 deletions(-)diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 21f851179ff0..7ccd4a80788c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig@@ -771,6 +771,7 @@ if HYPERVISOR_GUEST config PARAVIRT bool "Enable paravirtualization code" + depends on HAVE_STATIC_CALL help This changes the kernel so it can modify itself when it is run under a hypervisor, potentially improving performance significantlydiff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index 30f76b966857..b4ee331d29a7 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h@@ -63,7 +63,7 @@ typedef int (*hyperv_fill_flush_list_func)( static __always_inline void hv_setup_sched_clock(void *sched_clock) { #ifdef CONFIG_PARAVIRT - pv_ops.time.sched_clock = sched_clock; + paravirt_set_sched_clock(sched_clock); #endif }diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index 4abf110e2243..1e45b46fae84 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h@@ -15,11 +15,22 @@ #include <linux/bug.h> #include <linux/types.h> #include <linux/cpumask.h> +#include <linux/static_call_types.h> #include <asm/frame.h> -static inline unsigned long long paravirt_sched_clock(void) +u64 dummy_steal_clock(int cpu); +u64 dummy_sched_clock(void); + +DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock); +DECLARE_STATIC_CALL(pv_sched_clock, dummy_sched_clock);
Did you build this before sending?
I'm test-applying this on rc6 + tip/master so I probably am using a
different tree so it looks like something has changed in the meantime.
-rc6 has a couple of Xen changes which made applying those to need some
wiggling in...
Maybe you should redo them ontop of tip/master. That is, *if* they're
going to eventually go through tip. The diffstat has Xen stuff too so we
might need some synchronization here what goes where how...
./arch/x86/include/asm/paravirt.h:24:1: warning: data definition has no type or storage class
24 | DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
| ^~~~~~~~~~~~~~~~~~~
./arch/x86/include/asm/paravirt.h:24:1: error: type defaults to ‘int’ in declaration of ‘DECLARE_STATIC_CALL’ [-Werror=implicit-int]
./arch/x86/include/asm/paravirt.h:24:1: warning: parameter names (without types) in function declaration
./arch/x86/include/asm/paravirt.h:25:1: warning: data definition has no type or storage class
25 | DECLARE_STATIC_CALL(pv_sched_clock, dummy_sched_clock);
| ^~~~~~~~~~~~~~~~~~~
./arch/x86/include/asm/paravirt.h:25:1: error: type defaults to ‘int’ in declaration of ‘DECLARE_STATIC_CALL’ [-Werror=implicit-int]
./arch/x86/include/asm/paravirt.h:25:1: warning: parameter names (without types) in function declaration
./arch/x86/include/asm/paravirt.h: In function ‘paravirt_sched_clock’:
./arch/x86/include/asm/paravirt.h:33:9: error: implicit declaration of function ‘static_call’ [-Werror=implicit-function-declaration]
33 | return static_call(pv_sched_clock)();
| ^~~~~~~~~~~
./arch/x86/include/asm/paravirt.h:33:21: error: ‘pv_sched_clock’ undeclared (first use in this function); did you mean ‘dummy_sched_clock’?
33 | return static_call(pv_sched_clock)();
| ^~~~~~~~~~~~~~
| dummy_sched_clock
./arch/x86/include/asm/paravirt.h:33:21: note: each undeclared identifier is reported only once for each function it appears in
./arch/x86/include/asm/paravirt.h: In function ‘paravirt_steal_clock’:
./arch/x86/include/asm/paravirt.h:47:21: error: ‘pv_steal_clock’ undeclared (first use in this function); did you mean ‘dummy_steal_clock’?
47 | return static_call(pv_steal_clock)(cpu);
| ^~~~~~~~~~~~~~
| dummy_steal_clock
cc1: some warnings being treated as errors
make[1]: *** [scripts/Makefile.build:117: arch/x86/kernel/asm-offsets.s] Error 1
make: *** [Makefile:1200: prepare0] Error 2
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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