74 lines
2.5 KiB
Diff
74 lines
2.5 KiB
Diff
|
From 0fdb006a5af7f391a6de4ce810aba4af46c427e4 Mon Sep 17 00:00:00 2001
|
||
|
|
From: Andy Lutomirski <luto@amacapital.net>
|
||
|
|
Date: Fri, 5 Dec 2014 19:03:28 -0800
|
||
|
|
Subject: [PATCH] x86, kvm: Clear paravirt_enabled on KVM guests for espfix32's
|
||
|
|
benefit
|
||
|
|
|
||
|
|
paravirt_enabled has the following effects:
|
||
|
|
|
||
|
|
- Disables the F00F bug workaround warning. There is no F00F bug
|
||
|
|
workaround any more because Linux's standard IDT handling already
|
||
|
|
works around the F00F bug, but the warning still exists. This
|
||
|
|
is only cosmetic, and, in any event, there is no such thing as
|
||
|
|
KVM on a CPU with the F00F bug.
|
||
|
|
|
||
|
|
- Disables 32-bit APM BIOS detection. On a KVM paravirt system,
|
||
|
|
there should be no APM BIOS anyway.
|
||
|
|
|
||
|
|
- Disables tboot. I think that the tboot code should check the
|
||
|
|
CPUID hypervisor bit directly if it matters.
|
||
|
|
|
||
|
|
- paravirt_enabled disables espfix32. espfix32 should *not* be
|
||
|
|
disabled under KVM paravirt.
|
||
|
|
|
||
|
|
The last point is the purpose of this patch. It fixes a leak of the
|
||
|
|
high 16 bits of the kernel stack address on 32-bit KVM paravirt
|
||
|
|
guests.
|
||
|
|
|
||
|
|
While I'm at it, this removes pv_info setup from kvmclock. That
|
||
|
|
code seems to serve no purpose.
|
||
|
|
|
||
|
|
Cc: stable@vger.kernel.org
|
||
|
|
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
|
||
|
|
---
|
||
|
|
arch/x86/kernel/kvm.c | 9 ++++++++-
|
||
|
|
arch/x86/kernel/kvmclock.c | 2 --
|
||
|
|
2 files changed, 8 insertions(+), 3 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
|
||
|
|
index 3dd8e2c4d74a..07de51f66deb 100644
|
||
|
|
--- a/arch/x86/kernel/kvm.c
|
||
|
|
+++ b/arch/x86/kernel/kvm.c
|
||
|
|
@@ -282,7 +282,14 @@ NOKPROBE_SYMBOL(do_async_page_fault);
|
||
|
|
static void __init paravirt_ops_setup(void)
|
||
|
|
{
|
||
|
|
pv_info.name = "KVM";
|
||
|
|
- pv_info.paravirt_enabled = 1;
|
||
|
|
+
|
||
|
|
+ /*
|
||
|
|
+ * KVM isn't paravirt in the sense of paravirt_enabled. A KVM
|
||
|
|
+ * guest kernel works like a bare metal kernel with additional
|
||
|
|
+ * features, and paravirt_enabled is about features that are
|
||
|
|
+ * missing.
|
||
|
|
+ */
|
||
|
|
+ pv_info.paravirt_enabled = 0;
|
||
|
|
|
||
|
|
if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
|
||
|
|
pv_cpu_ops.io_delay = kvm_io_delay;
|
||
|
|
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
|
||
|
|
index d9156ceecdff..d4d9a8ad7893 100644
|
||
|
|
--- a/arch/x86/kernel/kvmclock.c
|
||
|
|
+++ b/arch/x86/kernel/kvmclock.c
|
||
|
|
@@ -263,8 +263,6 @@ void __init kvmclock_init(void)
|
||
|
|
#endif
|
||
|
|
kvm_get_preset_lpj();
|
||
|
|
clocksource_register_hz(&kvm_clock, NSEC_PER_SEC);
|
||
|
|
- pv_info.paravirt_enabled = 1;
|
||
|
|
- pv_info.name = "KVM";
|
||
|
|
|
||
|
|
if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT))
|
||
|
|
pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT);
|
||
|
|
--
|
||
|
|
2.1.0
|
||
|
|
|