[PATCH v14 02/25] x86/kvmclock: Remove page size requirement from wall_clock

Pavel Tatashin
2018-07-18T02:21:48Z

From: Thomas Gleixner <tglx@linutronix.de>

There is no requirement for wall_clock data to be page aligned or page
sized.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kernel/kvmclock.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 890e9e58e4bf..e9863639312c 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -46,14 +46,12 @@ early_param("no-kvmclock", parse_no_kvmclock);

/* Aligned to page sizes to match whats mapped via vsyscalls to userspace */
#define HV_CLOCK_SIZE (sizeof(struct pvclock_vsyscall_time_info) * NR_CPUS)
-#define WALL_CLOCK_SIZE (sizeof(struct pvclock_wall_clock))

static u8 hv_clock_mem[PAGE_ALIGN(HV_CLOCK_SIZE)] __aligned(PAGE_SIZE);
-static u8 wall_clock_mem[PAGE_ALIGN(WALL_CLOCK_SIZE)] __aligned(PAGE_SIZE);

/* The hypervisor will put information about time periodically here */
static struct pvclock_vsyscall_time_info *hv_clock;
-static struct pvclock_wall_clock *wall_clock;
+static struct pvclock_wall_clock wall_clock;

/*
* The wallclock is the time of day when we booted. Since then, some time may
@@ -66,15 +64,15 @@ static void kvm_get_wallclock(struct timespec64 *now)
int low, high;
int cpu;

- low = (int)slow_virt_to_phys(wall_clock);
- high = ((u64)slow_virt_to_phys(wall_clock) >> 32);
+ low = (int)slow_virt_to_phys(&wall_clock);
+ high = ((u64)slow_virt_to_phys(&wall_clock) >> 32);

native_write_msr(msr_kvm_wall_clock, low, high);

cpu = get_cpu();

vcpu_time = &hv_clock[cpu].pvti;
- pvclock_read_wallclock(wall_clock, vcpu_time, now);
+ pvclock_read_wallclock(&wall_clock, vcpu_time, now);

put_cpu();
}
@@ -266,12 +264,10 @@ void __init kvmclock_init(void)
} else if (!(kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)))
return;

- wall_clock = (struct pvclock_wall_clock *)wall_clock_mem;
hv_clock = (struct pvclock_vsyscall_time_info *)hv_clock_mem;

if (kvm_register_clock("primary cpu clock")) {
hv_clock = NULL;
- wall_clock = NULL;
return;
}

--
2.18.0