[PATCH v4 39/40] KVM: arm/arm64: Move VGIC APR save/restore to vgic put/load
Marc Zyngier
marc.zyngier at arm.com
Thu Feb 22 05:11:55 PST 2018
On 15/02/18 21:03, Christoffer Dall wrote:
> The APRs can only have bits set when the guest acknowledges an interrupt
> in the LR and can only have a bit cleared when the guest EOIs an
> interrupt in the LR. Therefore, if we have no LRs with any
> pending/active interrupts, the APR cannot change value and there is no
> need to clear it on every exit from the VM (hint: it will have already
> been cleared when we exited the guest the last time with the LRs all
> EOIed).
>
> The only case we need to take care of is when we migrate the VCPU away
> from a CPU or migrate a new VCPU onto a CPU, or when we return to
> userspace to capture the state of the VCPU for migration. To make sure
> this works, factor out the APR save/restore functionality into separate
> functions called from the VCPU (and by extension VGIC) put/load hooks.
>
> Signed-off-by: Christoffer Dall <christoffer.dall at linaro.org>
> ---
> arch/arm/include/asm/kvm_hyp.h | 2 +
> arch/arm64/include/asm/kvm_hyp.h | 2 +
> virt/kvm/arm/hyp/vgic-v3-sr.c | 124 +++++++++++++++++++++------------------
> virt/kvm/arm/vgic/vgic-v2.c | 7 +--
> virt/kvm/arm/vgic/vgic-v3.c | 5 ++
> 5 files changed, 78 insertions(+), 62 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_hyp.h b/arch/arm/include/asm/kvm_hyp.h
> index 1ab8329e9ff7..530a3c1cfe6f 100644
> --- a/arch/arm/include/asm/kvm_hyp.h
> +++ b/arch/arm/include/asm/kvm_hyp.h
> @@ -110,6 +110,8 @@ void __sysreg_restore_state(struct kvm_cpu_context *ctxt);
>
> void __vgic_v3_save_state(struct kvm_vcpu *vcpu);
> void __vgic_v3_restore_state(struct kvm_vcpu *vcpu);
> +void __vgic_v3_save_aprs(struct kvm_vcpu *vcpu);
> +void __vgic_v3_restore_aprs(struct kvm_vcpu *vcpu);
>
> asmlinkage void __vfp_save_state(struct vfp_hard_struct *vfp);
> asmlinkage void __vfp_restore_state(struct vfp_hard_struct *vfp);
> diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
> index febe417b8b4e..6f3929b2fcf7 100644
> --- a/arch/arm64/include/asm/kvm_hyp.h
> +++ b/arch/arm64/include/asm/kvm_hyp.h
> @@ -124,6 +124,8 @@ int __vgic_v2_perform_cpuif_access(struct kvm_vcpu *vcpu);
>
> void __vgic_v3_save_state(struct kvm_vcpu *vcpu);
> void __vgic_v3_restore_state(struct kvm_vcpu *vcpu);
> +void __vgic_v3_save_aprs(struct kvm_vcpu *vcpu);
> +void __vgic_v3_restore_aprs(struct kvm_vcpu *vcpu);
> int __vgic_v3_perform_cpuif_access(struct kvm_vcpu *vcpu);
>
> void __timer_enable_traps(struct kvm_vcpu *vcpu);
> diff --git a/virt/kvm/arm/hyp/vgic-v3-sr.c b/virt/kvm/arm/hyp/vgic-v3-sr.c
> index 9abf2f3c12b5..437d7af08683 100644
> --- a/virt/kvm/arm/hyp/vgic-v3-sr.c
> +++ b/virt/kvm/arm/hyp/vgic-v3-sr.c
> @@ -21,6 +21,7 @@
>
> #include <asm/kvm_emulate.h>
> #include <asm/kvm_hyp.h>
> +#include <asm/kvm_mmu.h>
>
> #define vtr_to_max_lr_idx(v) ((v) & 0xf)
> #define vtr_to_nr_pre_bits(v) ((((u32)(v) >> 26) & 7) + 1)
> @@ -221,14 +222,11 @@ void __hyp_text __vgic_v3_save_state(struct kvm_vcpu *vcpu)
>
> if (used_lrs) {
> int i;
> - u32 nr_pre_bits;
> u32 elrsr;
>
> elrsr = read_gicreg(ICH_ELSR_EL2);
>
> write_gicreg(0, ICH_HCR_EL2);
> - val = read_gicreg(ICH_VTR_EL2);
> - nr_pre_bits = vtr_to_nr_pre_bits(val);
>
> for (i = 0; i < used_lrs; i++) {
> if (elrsr & (1 << i))
> @@ -238,39 +236,10 @@ void __hyp_text __vgic_v3_save_state(struct kvm_vcpu *vcpu)
>
> __gic_v3_set_lr(0, i);
> }
> -
> - switch (nr_pre_bits) {
> - case 7:
> - cpu_if->vgic_ap0r[3] = __vgic_v3_read_ap0rn(3);
> - cpu_if->vgic_ap0r[2] = __vgic_v3_read_ap0rn(2);
> - case 6:
> - cpu_if->vgic_ap0r[1] = __vgic_v3_read_ap0rn(1);
> - default:
> - cpu_if->vgic_ap0r[0] = __vgic_v3_read_ap0rn(0);
> - }
> -
> - switch (nr_pre_bits) {
> - case 7:
> - cpu_if->vgic_ap1r[3] = __vgic_v3_read_ap1rn(3);
> - cpu_if->vgic_ap1r[2] = __vgic_v3_read_ap1rn(2);
> - case 6:
> - cpu_if->vgic_ap1r[1] = __vgic_v3_read_ap1rn(1);
> - default:
> - cpu_if->vgic_ap1r[0] = __vgic_v3_read_ap1rn(0);
> - }
> } else {
> if (static_branch_unlikely(&vgic_v3_cpuif_trap) ||
> cpu_if->its_vpe.its_vm)
> write_gicreg(0, ICH_HCR_EL2);
> -
> - cpu_if->vgic_ap0r[0] = 0;
> - cpu_if->vgic_ap0r[1] = 0;
> - cpu_if->vgic_ap0r[2] = 0;
> - cpu_if->vgic_ap0r[3] = 0;
> - cpu_if->vgic_ap1r[0] = 0;
> - cpu_if->vgic_ap1r[1] = 0;
> - cpu_if->vgic_ap1r[2] = 0;
> - cpu_if->vgic_ap1r[3] = 0;
> }
>
> val = read_gicreg(ICC_SRE_EL2);
> @@ -287,8 +256,6 @@ void __hyp_text __vgic_v3_restore_state(struct kvm_vcpu *vcpu)
> {
> struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
> u64 used_lrs = vcpu->arch.vgic_cpu.used_lrs;
> - u64 val;
> - u32 nr_pre_bits;
> int i;
>
> /*
> @@ -306,32 +273,9 @@ void __hyp_text __vgic_v3_restore_state(struct kvm_vcpu *vcpu)
> write_gicreg(cpu_if->vgic_vmcr, ICH_VMCR_EL2);
> }
>
> - val = read_gicreg(ICH_VTR_EL2);
> - nr_pre_bits = vtr_to_nr_pre_bits(val);
> -
> if (used_lrs) {
> write_gicreg(cpu_if->vgic_hcr, ICH_HCR_EL2);
>
> - switch (nr_pre_bits) {
> - case 7:
> - __vgic_v3_write_ap0rn(cpu_if->vgic_ap0r[3], 3);
> - __vgic_v3_write_ap0rn(cpu_if->vgic_ap0r[2], 2);
> - case 6:
> - __vgic_v3_write_ap0rn(cpu_if->vgic_ap0r[1], 1);
> - default:
> - __vgic_v3_write_ap0rn(cpu_if->vgic_ap0r[0], 0);
> - }
> -
> - switch (nr_pre_bits) {
> - case 7:
> - __vgic_v3_write_ap1rn(cpu_if->vgic_ap1r[3], 3);
> - __vgic_v3_write_ap1rn(cpu_if->vgic_ap1r[2], 2);
> - case 6:
> - __vgic_v3_write_ap1rn(cpu_if->vgic_ap1r[1], 1);
> - default:
> - __vgic_v3_write_ap1rn(cpu_if->vgic_ap1r[0], 0);
> - }
> -
> for (i = 0; i < used_lrs; i++)
> __gic_v3_set_lr(cpu_if->vgic_lr[i], i);
> } else {
> @@ -364,6 +308,72 @@ void __hyp_text __vgic_v3_restore_state(struct kvm_vcpu *vcpu)
> ICC_SRE_EL2);
> }
>
> +void __hyp_text __vgic_v3_save_aprs(struct kvm_vcpu *vcpu)
> +{
> + struct vgic_v3_cpu_if *cpu_if;
> + u64 val;
> + u32 nr_pre_bits;
> +
> + vcpu = kern_hyp_va(vcpu);
> + cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
> +
> + val = read_gicreg(ICH_VTR_EL2);
> + nr_pre_bits = vtr_to_nr_pre_bits(val);
> +
> + switch (nr_pre_bits) {
> + case 7:
> + cpu_if->vgic_ap0r[3] = __vgic_v3_read_ap0rn(3);
> + cpu_if->vgic_ap0r[2] = __vgic_v3_read_ap0rn(2);
> + case 6:
> + cpu_if->vgic_ap0r[1] = __vgic_v3_read_ap0rn(1);
> + default:
> + cpu_if->vgic_ap0r[0] = __vgic_v3_read_ap0rn(0);
> + }
> +
> + switch (nr_pre_bits) {
> + case 7:
> + cpu_if->vgic_ap1r[3] = __vgic_v3_read_ap1rn(3);
> + cpu_if->vgic_ap1r[2] = __vgic_v3_read_ap1rn(2);
> + case 6:
> + cpu_if->vgic_ap1r[1] = __vgic_v3_read_ap1rn(1);
> + default:
> + cpu_if->vgic_ap1r[0] = __vgic_v3_read_ap1rn(0);
> + }
> +}
> +
> +void __hyp_text __vgic_v3_restore_aprs(struct kvm_vcpu *vcpu)
> +{
> + struct vgic_v3_cpu_if *cpu_if;
> + u64 val;
> + u32 nr_pre_bits;
> +
> + vcpu = kern_hyp_va(vcpu);
> + cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
> +
> + val = read_gicreg(ICH_VTR_EL2);
> + nr_pre_bits = vtr_to_nr_pre_bits(val);
> +
> + switch (nr_pre_bits) {
> + case 7:
> + __vgic_v3_write_ap0rn(cpu_if->vgic_ap0r[3], 3);
> + __vgic_v3_write_ap0rn(cpu_if->vgic_ap0r[2], 2);
> + case 6:
> + __vgic_v3_write_ap0rn(cpu_if->vgic_ap0r[1], 1);
> + default:
> + __vgic_v3_write_ap0rn(cpu_if->vgic_ap0r[0], 0);
> + }
> +
> + switch (nr_pre_bits) {
> + case 7:
> + __vgic_v3_write_ap1rn(cpu_if->vgic_ap1r[3], 3);
> + __vgic_v3_write_ap1rn(cpu_if->vgic_ap1r[2], 2);
> + case 6:
> + __vgic_v3_write_ap1rn(cpu_if->vgic_ap1r[1], 1);
> + default:
> + __vgic_v3_write_ap1rn(cpu_if->vgic_ap1r[0], 0);
> + }
> +}
> +
> void __hyp_text __vgic_v3_init_lrs(void)
> {
> int max_lr_idx = vtr_to_max_lr_idx(read_gicreg(ICH_VTR_EL2));
> diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
> index 1e5f3eb6973d..ca7cfee9f353 100644
> --- a/virt/kvm/arm/vgic/vgic-v2.c
> +++ b/virt/kvm/arm/vgic/vgic-v2.c
> @@ -446,7 +446,6 @@ void vgic_v2_save_state(struct kvm_vcpu *vcpu)
> {
> struct kvm *kvm = vcpu->kvm;
> struct vgic_dist *vgic = &kvm->arch.vgic;
> - struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2;
> void __iomem *base = vgic->vctrl_base;
> u64 used_lrs = vcpu->arch.vgic_cpu.used_lrs;
>
> @@ -454,11 +453,8 @@ void vgic_v2_save_state(struct kvm_vcpu *vcpu)
> return;
>
> if (used_lrs) {
> - cpu_if->vgic_apr = readl_relaxed(base + GICH_APR);
> save_lrs(vcpu, base);
> writel_relaxed(0, base + GICH_HCR);
> - } else {
> - cpu_if->vgic_apr = 0;
> }
> }
>
> @@ -476,7 +472,6 @@ void vgic_v2_restore_state(struct kvm_vcpu *vcpu)
>
> if (used_lrs) {
> writel_relaxed(cpu_if->vgic_hcr, base + GICH_HCR);
> - writel_relaxed(cpu_if->vgic_apr, base + GICH_APR);
> for (i = 0; i < used_lrs; i++) {
> writel_relaxed(cpu_if->vgic_lr[i],
> base + GICH_LR0 + (i * 4));
> @@ -490,6 +485,7 @@ void vgic_v2_load(struct kvm_vcpu *vcpu)
> struct vgic_dist *vgic = &vcpu->kvm->arch.vgic;
>
> writel_relaxed(cpu_if->vgic_vmcr, vgic->vctrl_base + GICH_VMCR);
> + writel_relaxed(cpu_if->vgic_apr, vgic->vctrl_base + GICH_APR);
> }
>
> void vgic_v2_put(struct kvm_vcpu *vcpu)
> @@ -498,4 +494,5 @@ void vgic_v2_put(struct kvm_vcpu *vcpu)
> struct vgic_dist *vgic = &vcpu->kvm->arch.vgic;
>
> cpu_if->vgic_vmcr = readl_relaxed(vgic->vctrl_base + GICH_VMCR);
> + cpu_if->vgic_apr = readl_relaxed(vgic->vctrl_base + GICH_APR);
> }
> diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
> index b76e21f3e6bd..4bafcd1e6bb8 100644
> --- a/virt/kvm/arm/vgic/vgic-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-v3.c
> @@ -16,6 +16,7 @@
> #include <linux/kvm.h>
> #include <linux/kvm_host.h>
> #include <kvm/arm_vgic.h>
> +#include <asm/kvm_hyp.h>
> #include <asm/kvm_mmu.h>
> #include <asm/kvm_asm.h>
>
> @@ -587,6 +588,8 @@ void vgic_v3_load(struct kvm_vcpu *vcpu)
> */
> if (likely(cpu_if->vgic_sre))
> kvm_call_hyp(__vgic_v3_write_vmcr, cpu_if->vgic_vmcr);
> +
> + kvm_call_hyp(__vgic_v3_restore_aprs, vcpu);
> }
>
> void vgic_v3_put(struct kvm_vcpu *vcpu)
> @@ -595,4 +598,6 @@ void vgic_v3_put(struct kvm_vcpu *vcpu)
>
> if (likely(cpu_if->vgic_sre))
> cpu_if->vgic_vmcr = kvm_call_hyp(__vgic_v3_read_vmcr);
> +
> + kvm_call_hyp(__vgic_v3_save_aprs, vcpu);
> }
>
An unfortunate consequence of the save/restore de-aggregation process in
this series is that we end-up doing quite a few EL2 calls in the !VHE
case. We should probably think of consolidating those behind a single
EL2 call if they have a measurable impact.
In the meantime:
Reviewed-by: Marc Zyngier <marc.zyngier at arm.com>
M.
--
Jazz is not dead. It just smells funny...
More information about the linux-arm-kernel
mailing list