On Tue, Dec 01, 2015 at 12:44:26PM +0100, Christoffer Dall wrote: > On Tue, Dec 01, 2015 at 11:32:20AM +0000, Marc Zyngier wrote: > > On 30/11/15 19:50, Christoffer Dall wrote: > > > On Fri, Nov 27, 2015 at 06:49:58PM +0000, Marc Zyngier wrote: > > >> Implement the vgic-v3 save restore as a direct translation of > > >> the assembly code version. > > >> > > >> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> > > >> --- > > >> arch/arm64/kvm/hyp/Makefile | 1 + > > >> arch/arm64/kvm/hyp/hyp.h | 3 + > > >> arch/arm64/kvm/hyp/vgic-v3-sr.c | 222 ++++++++++++++++++++++++++++++++++++++++ > > >> 3 files changed, 226 insertions(+) > > >> create mode 100644 arch/arm64/kvm/hyp/vgic-v3-sr.c > > >> > > >> diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile > > >> index d8d5968..d1e38ce 100644 > > >> --- a/arch/arm64/kvm/hyp/Makefile > > >> +++ b/arch/arm64/kvm/hyp/Makefile > > >> @@ -3,3 +3,4 @@ > > >> # > > >> > > >> obj-$(CONFIG_KVM_ARM_HOST) += vgic-v2-sr.o > > >> +obj-$(CONFIG_KVM_ARM_HOST) += vgic-v3-sr.o > > >> diff --git a/arch/arm64/kvm/hyp/hyp.h b/arch/arm64/kvm/hyp/hyp.h > > >> index 78f25c4..a31cb6e 100644 > > >> --- a/arch/arm64/kvm/hyp/hyp.h > > >> +++ b/arch/arm64/kvm/hyp/hyp.h > > >> @@ -30,5 +30,8 @@ > > >> void __vgic_v2_save_state(struct kvm_vcpu *vcpu); > > >> void __vgic_v2_restore_state(struct kvm_vcpu *vcpu); > > >> > > >> +void __vgic_v3_save_state(struct kvm_vcpu *vcpu); > > >> +void __vgic_v3_restore_state(struct kvm_vcpu *vcpu); > > >> + > > >> #endif /* __ARM64_KVM_HYP_H__ */ > > >> > > >> diff --git a/arch/arm64/kvm/hyp/vgic-v3-sr.c b/arch/arm64/kvm/hyp/vgic-v3-sr.c > > >> new file mode 100644 > > >> index 0000000..b490db5 > > >> --- /dev/null > > >> +++ b/arch/arm64/kvm/hyp/vgic-v3-sr.c > > >> @@ -0,0 +1,222 @@ > > >> +/* > > >> + * Copyright (C) 2012-2015 - ARM Ltd > > >> + * Author: Marc Zyngier <marc.zyngier@xxxxxxx> > > >> + * > > >> + * This program is free software; you can redistribute it and/or modify > > >> + * it under the terms of the GNU General Public License version 2 as > > >> + * published by the Free Software Foundation. > > >> + * > > >> + * This program is distributed in the hope that it will be useful, > > >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of > > >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > > >> + * GNU General Public License for more details. > > >> + * > > >> + * You should have received a copy of the GNU General Public License > > >> + * along with this program. If not, see <http://www.gnu.org/licenses/>. > > >> + */ > > >> + > > >> +#include <linux/compiler.h> > > >> +#include <linux/irqchip/arm-gic-v3.h> > > >> +#include <linux/kvm_host.h> > > >> + > > >> +#include <asm/kvm_mmu.h> > > >> + > > >> +#include "hyp.h" > > >> + > > >> +/* > > >> + * We store LRs in reverse order to let the CPU deal with streaming > > >> + * access. Use this macro to make it look saner... > > >> + */ > > >> +#define LR_OFFSET(n) (15 - n) > > >> + > > >> +#define read_gicreg(r) \ > > >> + ({ \ > > >> + u64 reg; \ > > >> + asm volatile("mrs_s %0, " __stringify(r) : "=r" (reg)); \ > > >> + reg; \ > > >> + }) > > >> + > > >> +#define write_gicreg(v,r) \ > > >> + do { \ > > >> + u64 __val = (v); \ > > >> + asm volatile("msr_s " __stringify(r) ", %0" : : "r" (__val));\ > > >> + } while (0) > > > > > > remind me what the msr_s and mrs_s do compared to msr and mrs? > > > > They do the same job, only for the system registers which are not in the > > original ARMv8 architecture spec, and most likely not implemented by > > old(er) compilers. > > > > > are these the reason why we need separate macros to access the gic > > > registers compared to 'normal' sysregs? > > > > Indeed. > > > > >> + > > >> +/* vcpu is already in the HYP VA space */ > > >> +void __hyp_text __vgic_v3_save_state(struct kvm_vcpu *vcpu) > > >> +{ > > >> + struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3; > > >> + u64 val; > > >> + u32 nr_lr, nr_pri; > > >> + > > >> + /* > > >> + * Make sure stores to the GIC via the memory mapped interface > > >> + * are now visible to the system register interface. > > >> + */ > > >> + dsb(st); > > >> + > > >> + cpu_if->vgic_vmcr = read_gicreg(ICH_VMCR_EL2); > > >> + cpu_if->vgic_misr = read_gicreg(ICH_MISR_EL2); > > >> + cpu_if->vgic_eisr = read_gicreg(ICH_EISR_EL2); > > >> + cpu_if->vgic_elrsr = read_gicreg(ICH_ELSR_EL2); > > >> + > > >> + write_gicreg(0, ICH_HCR_EL2); > > >> + val = read_gicreg(ICH_VTR_EL2); > > >> + nr_lr = val & 0xf; > > > > > > this is not technically nr_lr, it's max_lr or max_lr_idx or something > > > like that. > > > > Let's go for max_lr_idx then. > > > > >> + nr_pri = ((u32)val >> 29) + 1; > > > > > > nit: nr_pri_bits > > > > > >> + > > >> + switch (nr_lr) { > > >> + case 15: > > >> + cpu_if->vgic_lr[LR_OFFSET(15)] = read_gicreg(ICH_LR15_EL2); > > >> + case 14: > > >> + cpu_if->vgic_lr[LR_OFFSET(14)] = read_gicreg(ICH_LR14_EL2); > > >> + case 13: > > >> + cpu_if->vgic_lr[LR_OFFSET(13)] = read_gicreg(ICH_LR13_EL2); > > >> + case 12: > > >> + cpu_if->vgic_lr[LR_OFFSET(12)] = read_gicreg(ICH_LR12_EL2); > > >> + case 11: > > >> + cpu_if->vgic_lr[LR_OFFSET(11)] = read_gicreg(ICH_LR11_EL2); > > >> + case 10: > > >> + cpu_if->vgic_lr[LR_OFFSET(10)] = read_gicreg(ICH_LR10_EL2); > > >> + case 9: > > >> + cpu_if->vgic_lr[LR_OFFSET(9)] = read_gicreg(ICH_LR9_EL2); > > >> + case 8: > > >> + cpu_if->vgic_lr[LR_OFFSET(8)] = read_gicreg(ICH_LR8_EL2); > > >> + case 7: > > >> + cpu_if->vgic_lr[LR_OFFSET(7)] = read_gicreg(ICH_LR7_EL2); > > >> + case 6: > > >> + cpu_if->vgic_lr[LR_OFFSET(6)] = read_gicreg(ICH_LR6_EL2); > > >> + case 5: > > >> + cpu_if->vgic_lr[LR_OFFSET(5)] = read_gicreg(ICH_LR5_EL2); > > >> + case 4: > > >> + cpu_if->vgic_lr[LR_OFFSET(4)] = read_gicreg(ICH_LR4_EL2); > > >> + case 3: > > >> + cpu_if->vgic_lr[LR_OFFSET(3)] = read_gicreg(ICH_LR3_EL2); > > >> + case 2: > > >> + cpu_if->vgic_lr[LR_OFFSET(2)] = read_gicreg(ICH_LR2_EL2); > > >> + case 1: > > >> + cpu_if->vgic_lr[LR_OFFSET(1)] = read_gicreg(ICH_LR1_EL2); > > >> + case 0: > > >> + cpu_if->vgic_lr[LR_OFFSET(0)] = read_gicreg(ICH_LR0_EL2); > > > > > > I don't understand this; LR_OFFSET(0) == (15 - 0) == 15, so > > > > > > cpu_if->vgic_lr[15] = read_gicreg(ICH_LR0_EL2) ? > > > > Just like in the assembly version. We store the LRs in the order we read > > them so that we don't confuse the CPU by writing backward (believe it or > > not, CPUs do get horribly confused if you do that). > > but aren't we storing the wrong register to the wrong index in the > array? > > Do we really access cpu_if->vgic_lr[15..12] in the C-code if the system > only has 4 LRs? > ok, I looked at the code myself (not sure why I didn't do that in the first place) and indeed we use a different but with similar results macro to access the array from the C code. This is just insane to me, and we don't have a comment on the data structure saying "this is not stored the way you'd think it is". Why can't we just do: cpu_if->vgic_lr[3] = read_gicreg(ICH_LR3_EL2); cpu_if->vgic_lr[2] = read_gicreg(ICH_LR2_EL2); cpu_if->vgic_lr[1] = read_gicreg(ICH_LR1_EL2); cpu_if->vgic_lr[0] = read_gicreg(ICH_LR0_EL2); ? -Christoffer -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
