On Tue, 20 Feb 2018, Julien Grall wrote: > Hi Stefano, > > On 19/02/18 21:58, Stefano Stabellini wrote: > > On big.LITTLE systems not all cores have the same midr. Instead of > > storing only one vpidr per domain, make it per vcpu and initialize it to > > the value of the midr of the pcpu where the vcpu will run. > > > > This way, assuming that the vcpu has been created with the right pcpu > > affinity, the guest will be able to read the right vpidr value, matching > > the one of the physical cpu. > > > > Signed-off-by: Stefano Stabellini <sstabell...@kernel.org> > > > > --- > > > > - remove warning message > > - make vpidr per vcpu > > --- > > xen/arch/arm/domain.c | 6 ++---- > > xen/arch/arm/vcpreg.c | 4 ++-- > > xen/include/asm-arm/domain.h | 6 +++--- > > 3 files changed, 7 insertions(+), 9 deletions(-) > > > > diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c > > index fb51415..41d5d25 100644 > > --- a/xen/arch/arm/domain.c > > +++ b/xen/arch/arm/domain.c > > @@ -180,7 +180,7 @@ static void ctxt_switch_to(struct vcpu *n) > > p2m_restore_state(n); > > - WRITE_SYSREG32(n->domain->arch.vpidr, VPIDR_EL2); > > + WRITE_SYSREG32(n->arch.vpidr, VPIDR_EL2); > > Do we really need to store the vpidr in struct vcpu? It would be simpler and > more efficient (no memory access) to use directly read MDIR_EL1 and copy it to > VPIDR_EL1.
I followed your suggestion to drop vpidr from struct vcpu and just read MDIR_EL1 in ctxt_switch_to. In do_cp14_32 I replaced v->arch.vpidr with current_cpu_data.midr.bits for simplicity. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
