[PATCH 4.4.y 040/101] x86/xen: Zero MSR_IA32_SPEC_CTRL before suspend
flat view
STALE3011d
REVIEWED: 4 (0M)
From: Srivatsa S. Bhat <hidden>
Date: 2018-07-13 22:10:47
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), xen hypervisor x86 · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Juergen Gross
4 review trailers.
From: Juergen Gross <jgross@suse.com> commit 71c208dd54ab971036d83ff6d9837bae4976e623 upstream. Older Xen versions (4.5 and before) might have problems migrating pv guests with MSR_IA32_SPEC_CTRL having a non-zero value. So before suspending zero that MSR and restore it after being resumed. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Thomas Gleixner <redacted> Reviewed-by: Jan Beulich <redacted> Cc: stable@vger.kernel.org Cc: xen-devel@lists.xenproject.org Cc: boris.ostrovsky@oracle.com Link: https://lkml.kernel.org/r/20180226140818.4849-1-jgross@suse.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Srivatsa S. Bhat <redacted> Reviewed-by: Matt Helsley (VMware) <redacted> Reviewed-by: Alexey Makhalov <redacted> Reviewed-by: Bo Gan <redacted> --- arch/x86/xen/suspend.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
index 7f664c4..4ecd0de 100644
--- a/arch/x86/xen/suspend.c
+++ b/arch/x86/xen/suspend.c@@ -1,11 +1,14 @@ #include <linux/types.h> #include <linux/tick.h> +#include <linux/percpu-defs.h> #include <xen/xen.h> #include <xen/interface/xen.h> #include <xen/grant_table.h> #include <xen/events.h> +#include <asm/cpufeatures.h> +#include <asm/msr-index.h> #include <asm/xen/hypercall.h> #include <asm/xen/page.h> #include <asm/fixmap.h>
@@ -68,6 +71,8 @@ static void xen_pv_post_suspend(int suspend_cancelled) xen_mm_unpin_all(); } +static DEFINE_PER_CPU(u64, spec_ctrl); + void xen_arch_pre_suspend(void) { if (xen_pv_domain())
@@ -84,6 +89,9 @@ void xen_arch_post_suspend(int cancelled) static void xen_vcpu_notify_restore(void *data) { + if (xen_pv_domain() && boot_cpu_has(X86_FEATURE_SPEC_CTRL)) + wrmsrl(MSR_IA32_SPEC_CTRL, this_cpu_read(spec_ctrl)); + /* Boot processor notified via generic timekeeping_resume() */ if (smp_processor_id() == 0) return;
@@ -93,7 +101,15 @@ static void xen_vcpu_notify_restore(void *data) static void xen_vcpu_notify_suspend(void *data) { + u64 tmp; + tick_suspend_local(); + + if (xen_pv_domain() && boot_cpu_has(X86_FEATURE_SPEC_CTRL)) { + rdmsrl(MSR_IA32_SPEC_CTRL, tmp); + this_cpu_write(spec_ctrl, tmp); + wrmsrl(MSR_IA32_SPEC_CTRL, 0); + } } void xen_arch_resume(void)