[gentoo-commits] proj/linux-patches:4.17 commit in: /

[Mike Pagano]

commit:     28232bbdc29fe4ef9f7d2a5360d7cdd000b26304
Author:     Mike Pagano <mpagano <AT> gentoo <DOT> org>
AuthorDate: Fri Jun 29 23:18:10 2018 +0000
Commit:     Mike Pagano <mpagano <AT> gentoo <DOT> org>
CommitDate: Fri Jun 29 23:18:10 2018 +0000
URL:        https://gitweb.gentoo.org/proj/linux-patches.git/commit/?id=28232bbd

kvmclock: Define pvclock_pvti_cpu0_va setter for X86_32. See bug #658544.

 0000_README                                        |  4 ++
 ...ne-pvclock-pvti-cpu0-va-setter-for-X86-32.patch | 55 ++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/0000_README b/0000_README
index daa330b..af14401 100644
--- a/0000_README
+++ b/0000_README
@@ -67,6 +67,10 @@ Patch:  1510_fs-enable-link-security-restrictions-by-default.patch
 From:   http://sources.debian.net/src/linux/3.16.7-ckt4-3/debian/patches/debian/fs-enable-link-security-restrictions-by-default.patch/
 Desc:   Enable link security restrictions by default.
 
+Patch:  1700_define-pvclock-pvti-cpu0-va-setter-for-X86-32.patch
+From:   https://marc.info/?l=kvm&m=152960320011592&w=2
+Desc:   kvmclock: Define pvclock_pvti_cpu0_va setter for X86_32. See bug #658544.
+
 Patch:  2300_enable-poweroff-on-Mac-Pro-11.patch
 From:   http://kernel.ubuntu.com/git/ubuntu/ubuntu-xenial.git/patch/drivers/pci/quirks.c?id=5080ff61a438f3dd80b88b423e1a20791d8a774c
 Desc:   Workaround to enable poweroff on Mac Pro 11. See bug #601964.

diff --git a/1700_define-pvclock-pvti-cpu0-va-setter-for-X86-32.patch b/1700_define-pvclock-pvti-cpu0-va-setter-for-X86-32.patch
new file mode 100644
index 0000000..0732c51
--- /dev/null
+++ b/1700_define-pvclock-pvti-cpu0-va-setter-for-X86-32.patch
@@ -0,0 +1,55 @@
+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")
+Reported-by: Andreas Steinmetz <ast@×××××.de>
+Signed-off-by: Radim Krčmář <rkrcmar@××××××.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 bf8d1eb7fca3..46ffa8327563 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;
+-- 
+2.18.0.rc2
+