diff mbox series

[10/26] KVM: arm64: Refactor vcpu_{read,write}_sys_reg

Message ID 20200422120050.3693593-11-maz@kernel.org (mailing list archive)
State New, archived
Headers show
Series KVM: arm64: Preliminary NV patches | expand

Commit Message

Marc Zyngier April 22, 2020, noon UTC 
Extract the direct HW accessors for later reuse.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 135 ++++++++++++++++++++++----------------
 1 file changed, 78 insertions(+), 57 deletions(-)

Comments

James Morse May 26, 2020, 4:28 p.m. UTC | #1 
Hi Marc,

On 22/04/2020 13:00, Marc Zyngier wrote:
> Extract the direct HW accessors for later reuse.

> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 51db934702b64..46f218982df8c 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c

> +u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)
> +{
> +	u64 val = 0x8badf00d8badf00d;
> +
> +	if (!vcpu->arch.sysregs_loaded_on_cpu) {
> +		goto memory_read;
>  	}
>  
> -immediate_write:
> +	if (__vcpu_read_sys_reg_from_cpu(reg, &val))
> +		return val;
> +
> +memory_read:
> +	return __vcpu_sys_reg(vcpu, reg);
> +}


The goto here is a bit odd, is it just an artefact of how we got here?
Is this easier on the eye?:
| u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)
| {
|	u64 val = 0x8badf00d8badf00d;
|
|	if (vcpu->arch.sysregs_loaded_on_cpu &&
|	    __vcpu_read_sys_reg_from_cpu(reg, &val))
|		return val;
|
| 	return __vcpu_sys_reg(vcpu, reg);
| }


> +void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
> +{
> +	if (!vcpu->arch.sysregs_loaded_on_cpu)
> +		goto memory_write;
> +
> +	if (__vcpu_write_sys_reg_to_cpu(val, reg))
> +		return;
> +
> +memory_write:
>  	 __vcpu_sys_reg(vcpu, reg) = val;
>  }

Again I think its clearer without the goto....


Regardless:
Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James
Marc Zyngier May 27, 2020, 10:04 a.m. UTC | #2 
On 2020-05-26 17:28, James Morse wrote:
> Hi Marc,
> 
> On 22/04/2020 13:00, Marc Zyngier wrote:
>> Extract the direct HW accessors for later reuse.
> 
>> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
>> index 51db934702b64..46f218982df8c 100644
>> --- a/arch/arm64/kvm/sys_regs.c
>> +++ b/arch/arm64/kvm/sys_regs.c
> 
>> +u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)
>> +{
>> +	u64 val = 0x8badf00d8badf00d;
>> +
>> +	if (!vcpu->arch.sysregs_loaded_on_cpu) {
>> +		goto memory_read;
>>  	}
>> 
>> -immediate_write:
>> +	if (__vcpu_read_sys_reg_from_cpu(reg, &val))
>> +		return val;
>> +
>> +memory_read:
>> +	return __vcpu_sys_reg(vcpu, reg);
>> +}
> 
> 
> The goto here is a bit odd, is it just an artefact of how we got here?

That's because a lot of this changes when NV gets added to the mix,
see [1].

> Is this easier on the eye?:
> | u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)
> | {
> |	u64 val = 0x8badf00d8badf00d;
> |
> |	if (vcpu->arch.sysregs_loaded_on_cpu &&
> |	    __vcpu_read_sys_reg_from_cpu(reg, &val))
> |		return val;
> |
> | 	return __vcpu_sys_reg(vcpu, reg);
> | }

Definitely. I don't mind reworking the NV branch so that the label
gets introduced there.

>> +void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
>> +{
>> +	if (!vcpu->arch.sysregs_loaded_on_cpu)
>> +		goto memory_write;
>> +
>> +	if (__vcpu_write_sys_reg_to_cpu(val, reg))
>> +		return;
>> +
>> +memory_write:
>>  	 __vcpu_sys_reg(vcpu, reg) = val;
>>  }
> 
> Again I think its clearer without the goto....
> 
> 
> Regardless:
> Reviewed-by: James Morse <james.morse@arm.com>

Thanks,

         M.

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/commit/?h=kvm-arm64/nv-5.7-rc1-WIP&id=11f3217d39a602cbfac7d08064c8b31afb57348e
diff mbox series

Patch

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 51db934702b64..46f218982df8c 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -64,11 +64,8 @@  static bool write_to_read_only(struct kvm_vcpu *vcpu,
 	return false;
 }
 
-u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)
+static bool __vcpu_read_sys_reg_from_cpu(int reg, u64 *val)
 {
-	if (!vcpu->arch.sysregs_loaded_on_cpu)
-		goto immediate_read;
-
 	/*
 	 * System registers listed in the switch are not saved on every
 	 * exit from the guest but are only saved on vcpu_put.
@@ -79,40 +76,37 @@  u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)
 	 * thread when emulating cross-VCPU communication.
 	 */
 	switch (reg) {
-	case CSSELR_EL1:	return read_sysreg_s(SYS_CSSELR_EL1);
-	case SCTLR_EL1:		return read_sysreg_s(SYS_SCTLR_EL12);
-	case ACTLR_EL1:		return read_sysreg_s(SYS_ACTLR_EL1);
-	case CPACR_EL1:		return read_sysreg_s(SYS_CPACR_EL12);
-	case TTBR0_EL1:		return read_sysreg_s(SYS_TTBR0_EL12);
-	case TTBR1_EL1:		return read_sysreg_s(SYS_TTBR1_EL12);
-	case TCR_EL1:		return read_sysreg_s(SYS_TCR_EL12);
-	case ESR_EL1:		return read_sysreg_s(SYS_ESR_EL12);
-	case AFSR0_EL1:		return read_sysreg_s(SYS_AFSR0_EL12);
-	case AFSR1_EL1:		return read_sysreg_s(SYS_AFSR1_EL12);
-	case FAR_EL1:		return read_sysreg_s(SYS_FAR_EL12);
-	case MAIR_EL1:		return read_sysreg_s(SYS_MAIR_EL12);
-	case VBAR_EL1:		return read_sysreg_s(SYS_VBAR_EL12);
-	case CONTEXTIDR_EL1:	return read_sysreg_s(SYS_CONTEXTIDR_EL12);
-	case TPIDR_EL0:		return read_sysreg_s(SYS_TPIDR_EL0);
-	case TPIDRRO_EL0:	return read_sysreg_s(SYS_TPIDRRO_EL0);
-	case TPIDR_EL1:		return read_sysreg_s(SYS_TPIDR_EL1);
-	case AMAIR_EL1:		return read_sysreg_s(SYS_AMAIR_EL12);
-	case CNTKCTL_EL1:	return read_sysreg_s(SYS_CNTKCTL_EL12);
-	case PAR_EL1:		return read_sysreg_s(SYS_PAR_EL1);
-	case DACR32_EL2:	return read_sysreg_s(SYS_DACR32_EL2);
-	case IFSR32_EL2:	return read_sysreg_s(SYS_IFSR32_EL2);
-	case DBGVCR32_EL2:	return read_sysreg_s(SYS_DBGVCR32_EL2);
+	case CSSELR_EL1:	*val = read_sysreg_s(SYS_CSSELR_EL1);	break;
+	case SCTLR_EL1:		*val = read_sysreg_s(SYS_SCTLR_EL12);	break;
+	case ACTLR_EL1:		*val = read_sysreg_s(SYS_ACTLR_EL1);	break;
+	case CPACR_EL1:		*val = read_sysreg_s(SYS_CPACR_EL12);	break;
+	case TTBR0_EL1:		*val = read_sysreg_s(SYS_TTBR0_EL12);	break;
+	case TTBR1_EL1:		*val = read_sysreg_s(SYS_TTBR1_EL12);	break;
+	case TCR_EL1:		*val = read_sysreg_s(SYS_TCR_EL12);	break;
+	case ESR_EL1:		*val = read_sysreg_s(SYS_ESR_EL12);	break;
+	case AFSR0_EL1:		*val = read_sysreg_s(SYS_AFSR0_EL12);	break;
+	case AFSR1_EL1:		*val = read_sysreg_s(SYS_AFSR1_EL12);	break;
+	case FAR_EL1:		*val = read_sysreg_s(SYS_FAR_EL12);	break;
+	case MAIR_EL1:		*val = read_sysreg_s(SYS_MAIR_EL12);	break;
+	case VBAR_EL1:		*val = read_sysreg_s(SYS_VBAR_EL12);	break;
+	case CONTEXTIDR_EL1:	*val = read_sysreg_s(SYS_CONTEXTIDR_EL12);break;
+	case TPIDR_EL0:		*val = read_sysreg_s(SYS_TPIDR_EL0);	break;
+	case TPIDRRO_EL0:	*val = read_sysreg_s(SYS_TPIDRRO_EL0);	break;
+	case TPIDR_EL1:		*val = read_sysreg_s(SYS_TPIDR_EL1);	break;
+	case AMAIR_EL1:		*val = read_sysreg_s(SYS_AMAIR_EL12);	break;
+	case CNTKCTL_EL1:	*val = read_sysreg_s(SYS_CNTKCTL_EL12);	break;
+	case PAR_EL1:		*val = read_sysreg_s(SYS_PAR_EL1);	break;
+	case DACR32_EL2:	*val = read_sysreg_s(SYS_DACR32_EL2);	break;
+	case IFSR32_EL2:	*val = read_sysreg_s(SYS_IFSR32_EL2);	break;
+	case DBGVCR32_EL2:	*val = read_sysreg_s(SYS_DBGVCR32_EL2);	break;
+	default:		return false;
 	}
 
-immediate_read:
-	return __vcpu_sys_reg(vcpu, reg);
+	return true;
 }
 
-void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
+static bool __vcpu_write_sys_reg_to_cpu(u64 val, int reg)
 {
-	if (!vcpu->arch.sysregs_loaded_on_cpu)
-		goto immediate_write;
-
 	/*
 	 * System registers listed in the switch are not restored on every
 	 * entry to the guest but are only restored on vcpu_load.
@@ -122,32 +116,59 @@  void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
 	 * set once, before running the VCPU, and never changed later.
 	 */
 	switch (reg) {
-	case CSSELR_EL1:	write_sysreg_s(val, SYS_CSSELR_EL1);	return;
-	case SCTLR_EL1:		write_sysreg_s(val, SYS_SCTLR_EL12);	return;
-	case ACTLR_EL1:		write_sysreg_s(val, SYS_ACTLR_EL1);	return;
-	case CPACR_EL1:		write_sysreg_s(val, SYS_CPACR_EL12);	return;
-	case TTBR0_EL1:		write_sysreg_s(val, SYS_TTBR0_EL12);	return;
-	case TTBR1_EL1:		write_sysreg_s(val, SYS_TTBR1_EL12);	return;
-	case TCR_EL1:		write_sysreg_s(val, SYS_TCR_EL12);	return;
-	case ESR_EL1:		write_sysreg_s(val, SYS_ESR_EL12);	return;
-	case AFSR0_EL1:		write_sysreg_s(val, SYS_AFSR0_EL12);	return;
-	case AFSR1_EL1:		write_sysreg_s(val, SYS_AFSR1_EL12);	return;
-	case FAR_EL1:		write_sysreg_s(val, SYS_FAR_EL12);	return;
-	case MAIR_EL1:		write_sysreg_s(val, SYS_MAIR_EL12);	return;
-	case VBAR_EL1:		write_sysreg_s(val, SYS_VBAR_EL12);	return;
-	case CONTEXTIDR_EL1:	write_sysreg_s(val, SYS_CONTEXTIDR_EL12); return;
-	case TPIDR_EL0:		write_sysreg_s(val, SYS_TPIDR_EL0);	return;
-	case TPIDRRO_EL0:	write_sysreg_s(val, SYS_TPIDRRO_EL0);	return;
-	case TPIDR_EL1:		write_sysreg_s(val, SYS_TPIDR_EL1);	return;
-	case AMAIR_EL1:		write_sysreg_s(val, SYS_AMAIR_EL12);	return;
-	case CNTKCTL_EL1:	write_sysreg_s(val, SYS_CNTKCTL_EL12);	return;
-	case PAR_EL1:		write_sysreg_s(val, SYS_PAR_EL1);	return;
-	case DACR32_EL2:	write_sysreg_s(val, SYS_DACR32_EL2);	return;
-	case IFSR32_EL2:	write_sysreg_s(val, SYS_IFSR32_EL2);	return;
-	case DBGVCR32_EL2:	write_sysreg_s(val, SYS_DBGVCR32_EL2);	return;
+	case CSSELR_EL1:	write_sysreg_s(val, SYS_CSSELR_EL1);	break;
+	case SCTLR_EL1:		write_sysreg_s(val, SYS_SCTLR_EL12);	break;
+	case ACTLR_EL1:		write_sysreg_s(val, SYS_ACTLR_EL1);	break;
+	case CPACR_EL1:		write_sysreg_s(val, SYS_CPACR_EL12);	break;
+	case TTBR0_EL1:		write_sysreg_s(val, SYS_TTBR0_EL12);	break;
+	case TTBR1_EL1:		write_sysreg_s(val, SYS_TTBR1_EL12);	break;
+	case TCR_EL1:		write_sysreg_s(val, SYS_TCR_EL12);	break;
+	case ESR_EL1:		write_sysreg_s(val, SYS_ESR_EL12);	break;
+	case AFSR0_EL1:		write_sysreg_s(val, SYS_AFSR0_EL12);	break;
+	case AFSR1_EL1:		write_sysreg_s(val, SYS_AFSR1_EL12);	break;
+	case FAR_EL1:		write_sysreg_s(val, SYS_FAR_EL12);	break;
+	case MAIR_EL1:		write_sysreg_s(val, SYS_MAIR_EL12);	break;
+	case VBAR_EL1:		write_sysreg_s(val, SYS_VBAR_EL12);	break;
+	case CONTEXTIDR_EL1:	write_sysreg_s(val, SYS_CONTEXTIDR_EL12);break;
+	case TPIDR_EL0:		write_sysreg_s(val, SYS_TPIDR_EL0);	break;
+	case TPIDRRO_EL0:	write_sysreg_s(val, SYS_TPIDRRO_EL0);	break;
+	case TPIDR_EL1:		write_sysreg_s(val, SYS_TPIDR_EL1);	break;
+	case AMAIR_EL1:		write_sysreg_s(val, SYS_AMAIR_EL12);	break;
+	case CNTKCTL_EL1:	write_sysreg_s(val, SYS_CNTKCTL_EL12);	break;
+	case PAR_EL1:		write_sysreg_s(val, SYS_PAR_EL1);	break;
+	case DACR32_EL2:	write_sysreg_s(val, SYS_DACR32_EL2);	break;
+	case IFSR32_EL2:	write_sysreg_s(val, SYS_IFSR32_EL2);	break;
+	case DBGVCR32_EL2:	write_sysreg_s(val, SYS_DBGVCR32_EL2);	break;
+	default:		return false;
+	}
+
+	return true;
+}
+
+u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg)
+{
+	u64 val = 0x8badf00d8badf00d;
+
+	if (!vcpu->arch.sysregs_loaded_on_cpu) {
+		goto memory_read;
 	}
 
-immediate_write:
+	if (__vcpu_read_sys_reg_from_cpu(reg, &val))
+		return val;
+
+memory_read:
+	return __vcpu_sys_reg(vcpu, reg);
+}
+
+void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg)
+{
+	if (!vcpu->arch.sysregs_loaded_on_cpu)
+		goto memory_write;
+
+	if (__vcpu_write_sys_reg_to_cpu(val, reg))
+		return;
+
+memory_write:
 	 __vcpu_sys_reg(vcpu, reg) = val;
 }