Hi Marc,
On 09/09/16 10:19, Marc Zyngier wrote:
> Hi Vladimir,
>
...
>>
>> +extern struct static_key_false kvm_gicv3_cpuif;
>
> I think we should follow the model set by kvm_vgic_global_state, which
> is declared in arm_vgic.h. Even better, we should *embed* the static key
> in this structure. This will reduce the clutter and we wouldn't have to
> deal with all the section stuff (the hyp_data thing is a good cleanup,
> but I'd like to see it as a separate patch if possible).
Yes, it is what I was thinking about too, but was not sure about which
way to go, so hyp_data seemed me something we might reuse latter.
However, I agree that we can defer hyp_data thing...
>
>> +
>> +static inline bool kvm_arm_support_gicv3_cpuif(void)
>> +{
>> + if (IS_ENABLED(CONFIG_ARM_GIC_V3))
>> + return !!cpuid_feature_extract(CPUID_EXT_PFR1, 28);
>> + else
>> + return false;
>> +}
>> +
>> #endif /* __ARM_KVM_HOST_H__ */
>> diff --git a/arch/arm/include/asm/kvm_hyp.h b/arch/arm/include/asm/kvm_hyp.h
>> index 6eaff28..bd9434e 100644
>> --- a/arch/arm/include/asm/kvm_hyp.h
>> +++ b/arch/arm/include/asm/kvm_hyp.h
>> @@ -23,8 +23,6 @@
>> #include <asm/kvm_mmu.h>
>> #include <asm/vfp.h>
>>
>> -#define __hyp_text __section(.hyp.text) notrace
>> -
>> #define __ACCESS_CP15(CRn, Op1, CRm, Op2) \
>> "mrc", "mcr", __stringify(p15, Op1, %0, CRn, CRm, Op2), u32
>> #define __ACCESS_CP15_64(Op1, CRm) \
>> diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h
>> index a2e75b8..e61a809 100644
>> --- a/arch/arm/include/asm/virt.h
>> +++ b/arch/arm/include/asm/virt.h
>> @@ -28,6 +28,9 @@
>> */
>> #define BOOT_CPU_MODE_MISMATCH PSR_N_BIT
>>
>> +#define __hyp_text __section(.hyp.text) notrace
>> +#define __hyp_data __section(.hyp.data)
>> +
>> #ifndef __ASSEMBLY__
>> #include <asm/cacheflush.h>
>>
>> @@ -87,6 +90,11 @@ extern char __hyp_idmap_text_end[];
>> /* The section containing the hypervisor text */
>> extern char __hyp_text_start[];
>> extern char __hyp_text_end[];
>> +
>> +/* The section containing the hypervisor data */
>> +extern char __hyp_data_start[];
>> +extern char __hyp_data_end[];
>> +
>> #endif
>>
>> #endif /* __ASSEMBLY__ */
>> diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
>> index d24e5dd..6d53824 100644
>> --- a/arch/arm/kernel/vmlinux.lds.S
>> +++ b/arch/arm/kernel/vmlinux.lds.S
>> @@ -25,6 +25,11 @@
>> *(.hyp.text) \
>> VMLINUX_SYMBOL(__hyp_text_end) = .;
>>
>> +#define HYPERVISOR_DATA \
>> + VMLINUX_SYMBOL(__hyp_data_start) = .; \
>> + *(.hyp.data) \
>> + VMLINUX_SYMBOL(__hyp_data_end) = .;
>> +
>> #define IDMAP_TEXT \
>> ALIGN_FUNCTION(); \
>> VMLINUX_SYMBOL(__idmap_text_start) = .; \
>> @@ -256,6 +261,7 @@ SECTIONS
>> */
>> DATA_DATA
>> CONSTRUCTORS
>> + HYPERVISOR_DATA
>
> If you follow my idea of of embedding the static key, we can defer all
> of this to another patch set.
I'm happy with your idea, so I'll drop this hunk.
>
>>
>> _edata = .;
>> }
>> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
>> index 75f130e..f966763 100644
>> --- a/arch/arm/kvm/arm.c
>> +++ b/arch/arm/kvm/arm.c
>> @@ -27,6 +27,7 @@
>> #include <linux/mman.h>
>> #include <linux/sched.h>
>> #include <linux/kvm.h>
>> +#include <linux/irqchip/arm-gic-v3.h>
>> #include <trace/events/kvm.h>
>> #include <kvm/arm_pmu.h>
>>
>> @@ -68,6 +69,9 @@ static bool vgic_present;
>>
>> static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled);
>>
>> +/* GIC system register CPU interface */
>> +__hyp_data DEFINE_STATIC_KEY_FALSE(kvm_gicv3_cpuif);
>> +
>> static void kvm_arm_set_running_vcpu(struct kvm_vcpu *vcpu)
>> {
>> BUG_ON(preemptible());
>> @@ -1178,6 +1182,14 @@ static int init_common_resources(void)
>> return -ENOMEM;
>> }
>>
>> + if (kvm_arm_support_gicv3_cpuif()) {
>
> Why do we need to check this? If we identify a GICv3 (as exposed by the
> host GIC driver), let's just use that.
True, will drop this.
>
>> + if (!gic_enable_sre())
>> + kvm_info("GIC CPU interface present but disabled by higher exception level\n");
>
> Do you really want to try and enable SRE there? It feels wrong, as it
> will already have been enabled by the host driver. Also, we don't
> support having GICv3 in a non-SRE configuration (firmware must expose a
> GICv2 in that case).
>
>> +
>> + static_branch_enable(&kvm_gicv3_cpuif);
>> + kvm_info("GIC system register CPU interface\n");
>> + }
>
> Can this whole hunk be moved to the vgic initialization instead?
>
I'll move it there.
>> +
>> return 0;
>> }
>>
>> @@ -1297,6 +1309,13 @@ static int init_hyp_mode(void)
>> goto out_err;
>> }
>>
>> + err = create_hyp_mappings(kvm_ksym_ref(__hyp_data_start),
>> + kvm_ksym_ref(__hyp_data_end), PAGE_HYP);
>> + if (err) {
>> + kvm_err("Cannot map hyp data section\n");
>> + goto out_err;
>> + }
>> +
>> err = create_hyp_mappings(kvm_ksym_ref(__start_rodata),
>> kvm_ksym_ref(__end_rodata), PAGE_HYP_RO);
>> if (err) {
>> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
>> index 3eda975..1da74e8 100644
>> --- a/arch/arm64/include/asm/kvm_host.h
>> +++ b/arch/arm64/include/asm/kvm_host.h
>> @@ -24,6 +24,9 @@
>>
>> #include <linux/types.h>
>> #include <linux/kvm_types.h>
>> +#include <linux/jump_label.h>
>> +
>> +#include <asm/cpufeature.h>
>> #include <asm/kvm.h>
>> #include <asm/kvm_asm.h>
>> #include <asm/kvm_mmio.h>
>> @@ -390,4 +393,16 @@ static inline void __cpu_init_stage2(void)
>> "PARange is %d bits, unsupported configuration!", parange);
>> }
>>
>> +extern struct static_key_false kvm_gicv3_cpuif;
>> +
>> +static inline bool kvm_arm_support_gicv3_cpuif(void)
>> +{
>> + int reg = read_system_reg(SYS_ID_AA64PFR0_EL1);
>> +
>> + if (IS_ENABLED(CONFIG_ARM_GIC_V3))
>> + return !!cpuid_feature_extract_unsigned_field(reg, ID_AA64PFR0_GIC_SHIFT);
>> +
>> + return false;
>> +}
>> +
>> #endif /* __ARM64_KVM_HOST_H__ */
>> diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
>> index cff5105..5c4ac82 100644
>> --- a/arch/arm64/include/asm/kvm_hyp.h
>> +++ b/arch/arm64/include/asm/kvm_hyp.h
>> @@ -23,8 +23,6 @@
>> #include <asm/kvm_mmu.h>
>> #include <asm/sysreg.h>
>>
>> -#define __hyp_text __section(.hyp.text) notrace
>> -
>> #define read_sysreg_elx(r,nvh,vh) \
>> ({ \
>> u64 reg; \
>> diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
>> index 1788545..c49426e 100644
>> --- a/arch/arm64/include/asm/virt.h
>> +++ b/arch/arm64/include/asm/virt.h
>> @@ -42,6 +42,9 @@
>> #define BOOT_CPU_MODE_EL1 (0xe11)
>> #define BOOT_CPU_MODE_EL2 (0xe12)
>>
>> +#define __hyp_text __section(.hyp.text) notrace
>> +#define __hyp_data __section(.hyp.data)
>> +
>> #ifndef __ASSEMBLY__
>>
>> #include <asm/ptrace.h>
>> @@ -95,6 +98,10 @@ extern char __hyp_idmap_text_end[];
>> extern char __hyp_text_start[];
>> extern char __hyp_text_end[];
>>
>> +/* The section containing the hypervisor data */
>> +extern char __hyp_data_start[];
>> +extern char __hyp_data_end[];
>> +
>> #endif /* __ASSEMBLY__ */
>>
>> #endif /* ! __ASM__VIRT_H */
>> diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
>> index 659963d..ea94a10 100644
>> --- a/arch/arm64/kernel/vmlinux.lds.S
>> +++ b/arch/arm64/kernel/vmlinux.lds.S
>> @@ -40,6 +40,11 @@ jiffies = jiffies_64;
>> *(.hyp.text) \
>> VMLINUX_SYMBOL(__hyp_text_end) = .;
>>
>> +#define HYPERVISOR_DATA \
>> + VMLINUX_SYMBOL(__hyp_data_start) = .; \
>> + .hyp.data : {*(.hyp.data)} \
>> + VMLINUX_SYMBOL(__hyp_data_end) = .;
>> +
>> #define IDMAP_TEXT \
>> . = ALIGN(SZ_4K); \
>> VMLINUX_SYMBOL(__idmap_text_start) = .; \
>> @@ -185,6 +190,7 @@ SECTIONS
>> _data = .;
>> _sdata = .;
>> RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
>> + HYPERVISOR_DATA
>> PECOFF_EDATA_PADDING
>> _edata = .;
>>
>> diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
>> index 5a84b45..cdc1360 100644
>> --- a/arch/arm64/kvm/hyp/switch.c
>> +++ b/arch/arm64/kvm/hyp/switch.c
>> @@ -126,17 +126,13 @@ static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu)
>> write_sysreg(0, vttbr_el2);
>> }
>>
>> -static hyp_alternate_select(__vgic_call_save_state,
>> - __vgic_v2_save_state, __vgic_v3_save_state,
>> - ARM64_HAS_SYSREG_GIC_CPUIF);
>> -
>> -static hyp_alternate_select(__vgic_call_restore_state,
>> - __vgic_v2_restore_state, __vgic_v3_restore_state,
>> - ARM64_HAS_SYSREG_GIC_CPUIF);
>> -
>> static void __hyp_text __vgic_save_state(struct kvm_vcpu *vcpu)
>> {
>> - __vgic_call_save_state()(vcpu);
>> + if (static_branch_unlikely(&kvm_gicv3_cpuif))
>> + __vgic_v3_save_state(vcpu);
>> + else
>> + __vgic_v2_save_state(vcpu);
>> +
>> write_sysreg(read_sysreg(hcr_el2) & ~HCR_INT_OVERRIDE, hcr_el2);
>> }
>>
>> @@ -149,7 +145,10 @@ static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu)
>> val |= vcpu->arch.irq_lines;
>> write_sysreg(val, hcr_el2);
>>
>> - __vgic_call_restore_state()(vcpu);
>> + if (static_branch_unlikely(&kvm_gicv3_cpuif))
>> + __vgic_v3_restore_state(vcpu);
>> + else
>> + __vgic_v2_restore_state(vcpu);
>> }
>>
>> static bool __hyp_text __true_value(void)
>>
>
> Thanks,
Thanks for feedback!
Vladimir
>
> M.
>
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