| Message ID | 20190115083315.11951-1-juergh@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | [SRU,Xenial] UBUNTU: SAUCE: Restore the IBRS host state on VMEXIT | expand |
On 15/01/2019 08:33, Juerg Haefliger wrote: > BugLink: https://bugs.launchpad.net/bugs/1764956 > > IBRS in Ubuntu can be controlled dynamically from userspace. Make sure > the correct state is restored on VMEXIT. > > Suggested-by: Gavin Guo <gavin.guo@canonical.com> > Signed-off-by: Juerg Haefliger <juergh@canonical.com> > --- > arch/x86/kernel/cpu/bugs.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c > index 15867c20ed1c..63d5b84e680b 100644 > --- a/arch/x86/kernel/cpu/bugs.c > +++ b/arch/x86/kernel/cpu/bugs.c > @@ -189,6 +189,10 @@ x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest) > if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD)) > hostval |= ssbd_tif_to_spec_ctrl(ti->flags); > > + /* IBRS dynamically controlled in MSR_SPEC_CTRL */ > + if (ibrs_enabled) > + hostval |= SPEC_CTRL_IBRS; > + > if (hostval != guestval) { > msrval = setguest ? guestval : hostval; > wrmsrl(MSR_IA32_SPEC_CTRL, msrval); > Makes sense. Acked-by: Colin Ian King <colin.king@canonical.com>
On Tue, Jan 15, 2019 at 4:33 PM Juerg Haefliger <juerg.haefliger@canonical.com> wrote: > > BugLink: https://bugs.launchpad.net/bugs/1764956 > > IBRS in Ubuntu can be controlled dynamically from userspace. Make sure > the correct state is restored on VMEXIT. > > Suggested-by: Gavin Guo <gavin.guo@canonical.com> > Signed-off-by: Juerg Haefliger <juergh@canonical.com> > --- > arch/x86/kernel/cpu/bugs.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c > index 15867c20ed1c..63d5b84e680b 100644 > --- a/arch/x86/kernel/cpu/bugs.c > +++ b/arch/x86/kernel/cpu/bugs.c > @@ -189,6 +189,10 @@ x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest) > if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD)) > hostval |= ssbd_tif_to_spec_ctrl(ti->flags); > > + /* IBRS dynamically controlled in MSR_SPEC_CTRL */ > + if (ibrs_enabled) > + hostval |= SPEC_CTRL_IBRS; > + > if (hostval != guestval) { > msrval = setguest ? guestval : hostval; > wrmsrl(MSR_IA32_SPEC_CTRL, msrval); > -- > 2.19.1 > > > -- > kernel-team mailing list > kernel-team@lists.ubuntu.com > https://lists.ubuntu.com/mailman/listinfo/kernel-team The kernel with the patch based on version v4.4.0-141.167 has been tested[1] and the bug cannot be reproduced. [1]. https://kernel.ubuntu.com/~juergh/lp1764956/ Acked-by: Gavin Guo <gavin.guo@canonical.com> Tested-by: Gavin Guo <gavin.guo@canonical.com>
On 15.01.19 09:33, Juerg Haefliger wrote: > BugLink: https://bugs.launchpad.net/bugs/1764956 > > IBRS in Ubuntu can be controlled dynamically from userspace. Make sure > the correct state is restored on VMEXIT. > > Suggested-by: Gavin Guo <gavin.guo@canonical.com> > Signed-off-by: Juerg Haefliger <juergh@canonical.com> > --- Applied to xenial/master-next. Thanks. -Stefan > arch/x86/kernel/cpu/bugs.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c > index 15867c20ed1c..63d5b84e680b 100644 > --- a/arch/x86/kernel/cpu/bugs.c > +++ b/arch/x86/kernel/cpu/bugs.c > @@ -189,6 +189,10 @@ x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest) > if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD)) > hostval |= ssbd_tif_to_spec_ctrl(ti->flags); > > + /* IBRS dynamically controlled in MSR_SPEC_CTRL */ > + if (ibrs_enabled) > + hostval |= SPEC_CTRL_IBRS; > + > if (hostval != guestval) { > msrval = setguest ? guestval : hostval; > wrmsrl(MSR_IA32_SPEC_CTRL, msrval); >
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 15867c20ed1c..63d5b84e680b 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -189,6 +189,10 @@ x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest) if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD)) hostval |= ssbd_tif_to_spec_ctrl(ti->flags); + /* IBRS dynamically controlled in MSR_SPEC_CTRL */ + if (ibrs_enabled) + hostval |= SPEC_CTRL_IBRS; + if (hostval != guestval) { msrval = setguest ? guestval : hostval; wrmsrl(MSR_IA32_SPEC_CTRL, msrval);
BugLink: https://bugs.launchpad.net/bugs/1764956 IBRS in Ubuntu can be controlled dynamically from userspace. Make sure the correct state is restored on VMEXIT. Suggested-by: Gavin Guo <gavin.guo@canonical.com> Signed-off-by: Juerg Haefliger <juergh@canonical.com> --- arch/x86/kernel/cpu/bugs.c | 4 ++++ 1 file changed, 4 insertions(+)