On Tue, Aug 30, 2016 at 7:15 PM, Christoffer Dall <
[email protected]> wrote:

> On Wed, Aug 24, 2016 at 04:50:08PM +0530, [email protected] wrote:
> > From: Vijaya Kumar K <[email protected]>
>


> > diff --git a/virt/kvm/arm/vgic/vgic-sys-reg-v3.c
> b/virt/kvm/arm/vgic/vgic-sys-reg-v3.c
> > new file mode 100644
> > index 0000000..581d053
> > --- /dev/null
> > +++ b/virt/kvm/arm/vgic/vgic-sys-reg-v3.c
> > @@ -0,0 +1,211 @@
> > +#include <linux/irqchip/arm-gic-v3.h>
> > +#include <linux/kvm.h>
> > +#include <linux/kvm_host.h>
> > +#include <kvm/iodev.h>
> > +#include <kvm/arm_vgic.h>
> > +#include <asm/kvm_emulate.h>
> > +#include <asm/kvm_arm.h>
> > +#include <asm/kvm_mmu.h>
> > +
> > +#include "vgic.h"
> > +#include "vgic-mmio.h"
> > +#include "sys_regs.h"
> > +
> > +static bool access_gic_ctlr(struct kvm_vcpu *vcpu, struct
> sys_reg_params *p,
> > +                         const struct sys_reg_desc *r)
> > +{
> > +     struct vgic_vmcr vmcr;
> > +
> > +     vgic_get_vmcr(vcpu, &vmcr);
> > +     if (p->is_write) {
> > +             vmcr.ctlr = (u32)p->regval;
> > +             vgic_set_vmcr(vcpu, &vmcr);
> > +     } else {
> > +             p->regval = vmcr.ctlr;
> > +     }
> > +
>
> really?  Have you looked at the spec and implementation of this or did
> you just copy the v2 code?
>
> The ICH_VMCR_EL2 register field mappings are not identical to the ctlr
> mappings.  I think this causes some rework for much of this patch, so
> I'll have a look at the next revision.
>

  ICH_VMCR_EL2.VEOIM &  ICH_VMCR_EL2.CBPR holds
ICC_CTLR_EL1.EOImode & ICC_CTLR_EL1.CBPR  respectively.
Remaining fields are Readonly except PHME. AFAIK, vgic is not
holding ICC_CTLR_EL1 except the fields in ICH_VMCR_EL2.

>
> > +     return true;
> > +}
> > +
> > +static bool access_gic_pmr(struct kvm_vcpu *vcpu, struct sys_reg_params
> *p,
> > +                        const struct sys_reg_desc *r)
> > +{
> > +     struct vgic_vmcr vmcr;
> > +
> > +     vgic_get_vmcr(vcpu, &vmcr);
> > +     if (p->is_write) {
> > +             vmcr.pmr = (u32)p->regval;
> > +             vgic_set_vmcr(vcpu, &vmcr);
> > +     } else {
> > +             p->regval = vmcr.pmr;
> > +     }
> > +
> > +     return true;
> > +}
> > +
> > +static bool access_gic_bpr0(struct kvm_vcpu *vcpu, struct
> sys_reg_params *p,
> > +                         const struct sys_reg_desc *r)
> > +{
> > +     struct vgic_vmcr vmcr;
> > +
> > +     vgic_get_vmcr(vcpu, &vmcr);
> > +     if (p->is_write) {
> > +             vmcr.bpr = (u32)p->regval;
> > +             vgic_set_vmcr(vcpu, &vmcr);
> > +     } else {
> > +             p->regval = vmcr.bpr;
> > +     }
> > +
> > +     return true;
> > +}
> > +
> > +static bool access_gic_bpr1(struct kvm_vcpu *vcpu, struct
> sys_reg_params *p,
> > +                         const struct sys_reg_desc *r)
> > +{
> > +     struct vgic_vmcr vmcr;
> > +
> > +     vgic_get_vmcr(vcpu, &vmcr);
> > +     if (p->is_write) {
> > +             vmcr.abpr = (u32)p->regval;
> > +             vgic_set_vmcr(vcpu, &vmcr);
> > +     } else {
> > +             p->regval = vmcr.abpr;
> > +     }
> > +
> > +     return true;
> > +}
> > +
> > +static bool access_gic_grpen0(struct kvm_vcpu *vcpu, struct
> sys_reg_params *p,
> > +                           const struct sys_reg_desc *r)
> > +{
> > +     struct vgic_v3_cpu_if *vgicv3 = &vcpu->arch.vgic_cpu.vgic_v3;
> > +
> > +     if (p->is_write) {
> > +             vgicv3->vgic_vmcr &= ~ICH_VMCR_ENG0;
> > +             vgicv3->vgic_vmcr |= (p->regval << ICH_VMCR_ENG0_SHIFT) &
> > +                                   ICH_VMCR_ENG0;
> > +     } else {
> > +             p->regval = (vgicv3->vgic_vmcr & ICH_VMCR_ENG0) >>
> > +                          ICH_VMCR_ENG0_SHIFT;
> > +     }
>
> so for example, why shouldn't these go through the vgic_set/get_vmcr
> wrappers?
>

The vgic_vmcr struct as below is not managing ENG0 and ENG1 fields.
So could not use vgic_set/get wrappers.

struct vgic_vmcr {
        u32     ctlr;
        u32     abpr;
        u32     bpr;
        u32     pmr;
};



>
> > +
> > +     return true;
> > +}
> > +
> > +static bool access_gic_grpen1(struct kvm_vcpu *vcpu, struct
> sys_reg_params *p,
> > +                           const struct sys_reg_desc *r)
> > +{
> > +     struct vgic_v3_cpu_if *vgicv3 = &vcpu->arch.vgic_cpu.vgic_v3;
> > +
> > +     if (p->is_write) {
> > +             vgicv3->vgic_vmcr &= ~ICH_VMCR_ENG1;
> > +             vgicv3->vgic_vmcr |= (p->regval << ICH_VMCR_ENG1_SHIFT) &
> > +                                   ICH_VMCR_ENG1;
> > +     } else {
> > +             p->regval = (vgicv3->vgic_vmcr & ICH_VMCR_ENG1) >>
> > +                          ICH_VMCR_ENG1_SHIFT;
> > +     }
> > +
> > +     return true;
> > +}
> > +
> > +static bool access_gic_ap0r(struct kvm_vcpu *vcpu, struct
> sys_reg_params *p,
> > +                         const struct sys_reg_desc *r)
> > +{
> > +     struct vgic_v3_cpu_if *vgicv3 = &vcpu->arch.vgic_cpu.vgic_v3;
> > +     u8 idx = r->Op2 & 3;
> > +
> > +     if (p->is_write)
> > +             vgicv3->vgic_ap0r[idx] = p->regval;
> > +     else
> > +             p->regval = vgicv3->vgic_ap0r[idx];
> > +
> > +     return true;
> > +}
> > +
> > +static bool access_gic_ap1r(struct kvm_vcpu *vcpu, struct
> sys_reg_params *p,
> > +                         const struct sys_reg_desc *r)
> > +{
> > +     struct vgic_v3_cpu_if *vgicv3 = &vcpu->arch.vgic_cpu.vgic_v3;
> > +     u8 idx = r->Op2 & 3;
> > +
> > +     if (p->is_write)
> > +             vgicv3->vgic_ap1r[idx] = p->regval;
> > +     else
> > +             p->regval = vgicv3->vgic_ap1r[idx];
> > +
> > +     return true;
> > +}
> > +
> > +static const struct sys_reg_desc gic_v3_icc_reg_descs[] = {
> > +     /* ICC_PMR_EL1 */
> > +     { Op0(3), Op1(0), CRn(4), CRm(6), Op2(0), access_gic_pmr },
> > +     /* ICC_BPR0_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(8), Op2(3), access_gic_bpr0 },
> > +     /* ICC_AP0R0_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(8), Op2(4), access_gic_ap0r },
> > +     /* ICC_AP0R1_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(8), Op2(5), access_gic_ap0r },
> > +     /* ICC_AP0R2_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(8), Op2(6), access_gic_ap0r },
> > +     /* ICC_AP0R3_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(8), Op2(7), access_gic_ap0r },
> > +     /* ICC_AP1R0_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(9), Op2(0), access_gic_ap1r },
> > +     /* ICC_AP1R1_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(9), Op2(1), access_gic_ap1r },
> > +     /* ICC_AP1R2_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(9), Op2(2), access_gic_ap1r },
> > +     /* ICC_AP1R3_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(9), Op2(3), access_gic_ap1r },
> > +     /* ICC_BPR1_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(12), Op2(3), access_gic_bpr1 },
> > +     /* ICC_CTLR_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(12), Op2(4), access_gic_ctlr },
> > +     /* ICC_IGRPEN0_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(12), Op2(6), access_gic_grpen0 },
> > +     /* ICC_GRPEN1_EL1 */
> > +     { Op0(3), Op1(0), CRn(12), CRm(12), Op2(7), access_gic_grpen1 },
>
> Do we need to allow userspace to at least read ICC_SRE_EL1?


ICC_SRE_EL1.SRE is enabled at vgic initialization and DIB and FDB are not
configured.
    So save and restore does not make any effect.


> Should we verify that the DIB and FDB fields of that register are
> written as the system understands them (clear, WI)?
>

  What kind of verification we can do on DIB and FDB by userspace?.

>
> > +
> > +int vgic_v3_cpu_sysregs_uaccess(struct kvm_vcpu *vcpu, bool is_write,
> u64 id,
> > +                             u64 *reg)
> > +{
> > +     struct sys_reg_params params;
> > +     const struct sys_reg_desc *r;
> > +
> > +     if (is_write)
> > +             params.regval = le64_to_cpu(*reg);
>
> why do we need this conversion here?
>
>    The registers are managed in LE mode. So here the value to be
writtern is coverted to LE mode and similarly on reading back it is
converted
from LE.

> +     params.is_write = is_write;
> > +     params.is_aarch32 = false;
> > +     params.is_32bit = false;
> > +
> > +     r = find_reg_by_id(id, &params, gic_v3_icc_reg_descs,
> > +                        ARRAY_SIZE(gic_v3_icc_reg_descs));
> > +     if (!r)
> > +             return -ENXIO;
> > +
> > +     if (!r->access(vcpu, &params, r))
> > +             return -EINVAL;
> > +
> > +     if (!is_write)
> > +             *reg = cpu_to_le64(params.regval);
>
> same question as above
>
>
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