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| author | Andy Lutomirski <luto@kernel.org> | 2020-06-26 10:24:30 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2020-07-01 15:27:20 +0200 |
| commit | d029bff60aa6c7eab281d52602b6a7a971615324 (patch) | |
| tree | bc6aadea2b2a234361696aff4a6a9d2ac1564d36 | |
| parent | 40c45904f818c1f6555294ca27afc5fda4f09e68 (diff) | |
| download | linux-d029bff60aa6c7eab281d52602b6a7a971615324.tar.gz linux-d029bff60aa6c7eab281d52602b6a7a971615324.tar.bz2 linux-d029bff60aa6c7eab281d52602b6a7a971615324.zip | |
x86/fsgsbase: Fix Xen PV support
On Xen PV, SWAPGS doesn't work. Teach __rdfsbase_inactive() and
__wrgsbase_inactive() to use rdmsrl()/wrmsrl() on Xen PV. The Xen
pvop code will understand this and issue the correct hypercalls.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/f07c08f178fe9711915862b656722a207cd52c28.1593192140.git.luto@kernel.org
| -rw-r--r-- | arch/x86/kernel/process_64.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index cb8e37d3acaa..e14476f0c533 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -163,9 +163,15 @@ static noinstr unsigned long __rdgsbase_inactive(void) lockdep_assert_irqs_disabled(); - native_swapgs(); - gsbase = rdgsbase(); - native_swapgs(); + if (!static_cpu_has(X86_FEATURE_XENPV)) { + native_swapgs(); + gsbase = rdgsbase(); + native_swapgs(); + } else { + instrumentation_begin(); + rdmsrl(MSR_KERNEL_GS_BASE, gsbase); + instrumentation_end(); + } return gsbase; } @@ -182,9 +188,15 @@ static noinstr void __wrgsbase_inactive(unsigned long gsbase) { lockdep_assert_irqs_disabled(); - native_swapgs(); - wrgsbase(gsbase); - native_swapgs(); + if (!static_cpu_has(X86_FEATURE_XENPV)) { + native_swapgs(); + wrgsbase(gsbase); + native_swapgs(); + } else { + instrumentation_begin(); + wrmsrl(MSR_KERNEL_GS_BASE, gsbase); + instrumentation_end(); + } } /* |