| Message ID | 1435203028-23142-4-git-send-email-m.smarduch@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jun 24, 2015 at 08:30:28PM -0700, Mario Smarduch wrote: > This patch implements host KVM interface to Hyp mode VFP function to > switch out guest and switch in host. > > Signed-off-by: Mario Smarduch <m.smarduch@samsung.com> > --- > arch/arm/kvm/arm.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index d9631ec..77b41f5 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -105,6 +105,17 @@ void kvm_arch_check_processor_compat(void *rtn) > *(int *)rtn = 0; > } > > +/** > + * kvm_switch_vp_regs() - switch guest/host VFP registers > + * @vcpu: pointer to vcpu structure. > + * > + * HYP interface functions to save guest and restore host VFP registers Not sure I understand what you mean to say with this line, how about: Calls an assembly routine in HYP mode to actually perform the state save/restore. However, why do we actually need to do this in hyp mode? Can't we just as well do this in SVC mode or are we changing some trap settings here? > + */ > +static void kvm_switch_fp_regs(struct kvm_vcpu *vcpu) should probalby be called kvm_vcpu_put_fp_regs > +{ > + if (vcpu->arch.vfp_guest_saved == 1) > + kvm_call_hyp(__kvm_restore_host_vfp_state, vcpu); > +} > > /** > * kvm_arch_init_vm - initializes a VM data structure > @@ -292,6 +303,10 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) > > void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) > { > + > + /* Check if Guest accessed VFP registers */ > + kvm_switch_fp_regs(vcpu); > + > /* > * The arch-generic KVM code expects the cpu field of a vcpu to be -1 > * if the vcpu is no longer assigned to a cpu. This is used for the > -- > 1.7.9.5 How are we sure that the kernel never touches VFP registers between VCPU exit and kvm_arch_vcpu_put? Can a kernel-side memcpy implementation use the FP regs or something like that? Thanks, -Christoffer
On 07/05/2015 12:37 PM, Christoffer Dall wrote: > On Wed, Jun 24, 2015 at 08:30:28PM -0700, Mario Smarduch wrote: >> This patch implements host KVM interface to Hyp mode VFP function to >> switch out guest and switch in host. >> >> Signed-off-by: Mario Smarduch <m.smarduch@samsung.com> >> --- >> arch/arm/kvm/arm.c | 15 +++++++++++++++ >> 1 file changed, 15 insertions(+) >> >> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c >> index d9631ec..77b41f5 100644 >> --- a/arch/arm/kvm/arm.c >> +++ b/arch/arm/kvm/arm.c >> @@ -105,6 +105,17 @@ void kvm_arch_check_processor_compat(void *rtn) >> *(int *)rtn = 0; >> } >> >> +/** >> + * kvm_switch_vp_regs() - switch guest/host VFP registers >> + * @vcpu: pointer to vcpu structure. >> + * >> + * HYP interface functions to save guest and restore host VFP registers > > Not sure I understand what you mean to say with this line, how about: > > Calls an assembly routine in HYP mode to actually perform the state > save/restore. > > However, why do we actually need to do this in hyp mode? Can't we just > as well do this in SVC mode or are we changing some trap settings here? Yes it should be since non hyp registers are accessed. I reuse it since all the code was there to do the switch. > >> + */ >> +static void kvm_switch_fp_regs(struct kvm_vcpu *vcpu) > > should probalby be called kvm_vcpu_put_fp_regs > >> +{ >> + if (vcpu->arch.vfp_guest_saved == 1) >> + kvm_call_hyp(__kvm_restore_host_vfp_state, vcpu); >> +} >> >> /** >> * kvm_arch_init_vm - initializes a VM data structure >> @@ -292,6 +303,10 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) >> >> void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) >> { >> + >> + /* Check if Guest accessed VFP registers */ >> + kvm_switch_fp_regs(vcpu); >> + >> /* >> * The arch-generic KVM code expects the cpu field of a vcpu to be -1 >> * if the vcpu is no longer assigned to a cpu. This is used for the >> -- >> 1.7.9.5 > > How are we sure that the kernel never touches VFP registers between VCPU > exit and kvm_arch_vcpu_put? Can a kernel-side memcpy implementation use > the FP regs or something like that? Exceptions, interrupts - don't save any VFP context, if these VFP registers are touched by the kernel they should be saved/restored. The x86 version appears to the same. > > Thanks, > -Christoffer >
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index d9631ec..77b41f5 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -105,6 +105,17 @@ void kvm_arch_check_processor_compat(void *rtn) *(int *)rtn = 0; } +/** + * kvm_switch_vp_regs() - switch guest/host VFP registers + * @vcpu: pointer to vcpu structure. + * + * HYP interface functions to save guest and restore host VFP registers + */ +static void kvm_switch_fp_regs(struct kvm_vcpu *vcpu) +{ + if (vcpu->arch.vfp_guest_saved == 1) + kvm_call_hyp(__kvm_restore_host_vfp_state, vcpu); +} /** * kvm_arch_init_vm - initializes a VM data structure @@ -292,6 +303,10 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) { + + /* Check if Guest accessed VFP registers */ + kvm_switch_fp_regs(vcpu); + /* * The arch-generic KVM code expects the cpu field of a vcpu to be -1 * if the vcpu is no longer assigned to a cpu. This is used for the
This patch implements host KVM interface to Hyp mode VFP function to switch out guest and switch in host. Signed-off-by: Mario Smarduch <m.smarduch@samsung.com> --- arch/arm/kvm/arm.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)