Re: [Xen-devel] [PATCH v4 7/7] xen/x86: use PCID feature

On 03/04/18 09:14, Juergen Gross wrote: > On 29/03/18 17:37, Jan Beulich wrote: > On 29.03.18 at 17:15, wrote: >>> On 29/03/18 16:19, Jan Beulich wrote: >>> On 27.03.18 at 11:07, wrote: > @@ -102,7 +103,21 @@ void write_cr3_cr4(unsigned long cr3,

Re: [Xen-devel] [PATCH v4 7/7] xen/x86: use PCID feature

On 29/03/18 17:37, Jan Beulich wrote: On 29.03.18 at 17:15, wrote: >> On 29/03/18 16:19, Jan Beulich wrote: >> On 27.03.18 at 11:07, wrote: @@ -102,7 +103,21 @@ void write_cr3_cr4(unsigned long cr3, unsigned long cr4) t =

Re: [Xen-devel] [PATCH v4 7/7] xen/x86: use PCID feature

>>> On 29.03.18 at 17:15, wrote: > On 29/03/18 16:19, Jan Beulich wrote: > On 27.03.18 at 11:07, wrote: >>> @@ -102,7 +103,21 @@ void write_cr3_cr4(unsigned long cr3, unsigned long >>> cr4) >>> t = pre_flush(); >>> >>> if ( read_cr4() &

Re: [Xen-devel] [PATCH v4 7/7] xen/x86: use PCID feature

On 29/03/18 16:19, Jan Beulich wrote: On 27.03.18 at 11:07, wrote: >> --- a/xen/arch/x86/domain_page.c >> +++ b/xen/arch/x86/domain_page.c >> @@ -51,7 +51,7 @@ static inline struct vcpu *mapcache_current_vcpu(void) >> if ( (v = idle_vcpu[smp_processor_id()]) ==

Re: [Xen-devel] [PATCH v4 7/7] xen/x86: use PCID feature

>>> On 27.03.18 at 11:07, wrote: > --- a/xen/arch/x86/domain_page.c > +++ b/xen/arch/x86/domain_page.c > @@ -51,7 +51,7 @@ static inline struct vcpu *mapcache_current_vcpu(void) > if ( (v = idle_vcpu[smp_processor_id()]) == current ) >

[Xen-devel] [PATCH v4 7/7] xen/x86: use PCID feature

Avoid flushing the complete TLB when switching %cr3 for mitigation of Meltdown by using the PCID feature if available. We are using 4 PCID values for a 64 bit pv domain subject to XPTI and 2 values for the non-XPTI case: - guest active and in kernel mode - guest active and in user mode -