From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= <rkrcmar@redhat.com>
Date: Sun, 15 Jul 2018 17:43:11 +0200
Patch-mainline: 4.18
Git-commit: 94ffba484663ab3fc695ce2a34871e8c3db499f7
References: bsc#1098382
Subject: [PATCH] x86/kvmclock: set pvti_cpu0_va after enabling kvmclock
MIME-Version: 1.0
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pvti_cpu0_va is the address of shared kvmclock data structure.
pvti_cpu0_va is currently kept unset (1) on 32 bit systems, (2) when
kvmclock vsyscall is disabled, and (3) if kvmclock is not stable.
This poses a problem, because kvm_ptp needs pvti_cpu0_va, but (1) can
work on 32 bit, (2) has little relation to the vsyscall, and (3) does
not need stable kvmclock (although kvmclock won't be used for system
clock if it's not stable, so kvm_ptp is pointless in that case).
Expose pvti_cpu0_va whenever kvmclock is enabled to allow all users to
work with it.
This fixes a regression found on Gentoo: https://bugs.gentoo.org/658544.
Fixes: 9f08890ab906 ("x86/pvclock: add setter for pvclock_pvti_cpu0_va")
Cc: stable@vger.kernel.org
Reported-by: Andreas Steinmetz <ast@domdv.de>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/kernel/kvmclock.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 8b26c9e01cc4..d79a18b4cf9d 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -319,6 +319,8 @@ void __init kvmclock_init(void)
printk(KERN_INFO "kvm-clock: Using msrs %x and %x",
msr_kvm_system_time, msr_kvm_wall_clock);
+ pvclock_set_pvti_cpu0_va(hv_clock);
+
if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT))
pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT);
@@ -366,14 +368,11 @@ int __init kvm_setup_vsyscall_timeinfo(void)
vcpu_time = &hv_clock[cpu].pvti;
flags = pvclock_read_flags(vcpu_time);
- if (!(flags & PVCLOCK_TSC_STABLE_BIT)) {
- put_cpu();
- return 1;
- }
-
- pvclock_set_pvti_cpu0_va(hv_clock);
put_cpu();
+ if (!(flags & PVCLOCK_TSC_STABLE_BIT))
+ return 1;
+
kvm_clock.archdata.vclock_mode = VCLOCK_PVCLOCK;
#endif
return 0;
--
2.16.4