Re: [PATCH 05/59] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set

2019-06-24 Thread Dave Martin 
On Fri, Jun 21, 2019 at 10:37:49AM +0100, Marc Zyngier wrote:
> From: Christoffer Dall 
> 
> Reset the VCPU with PSTATE.M = EL2h when the nested virtualization
> feature is enabled on the VCPU.
> 
> Signed-off-by: Christoffer Dall 
> Signed-off-by: Marc Zyngier 
> ---
>  arch/arm64/kvm/reset.c | 7 +++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
> index 1140b4485575..675ca07dbb05 100644
> --- a/arch/arm64/kvm/reset.c
> +++ b/arch/arm64/kvm/reset.c
> @@ -52,6 +52,11 @@ static const struct kvm_regs default_regs_reset = {
>   PSR_F_BIT | PSR_D_BIT),
>  };
>  
> +static const struct kvm_regs default_regs_reset_el2 = {
> + .regs.pstate = (PSR_MODE_EL2h | PSR_A_BIT | PSR_I_BIT |
> + PSR_F_BIT | PSR_D_BIT),
> +};
> +

Is it worth having a #define for the common non-mode bits?  It's a bit
weird for EL2 and EL1 to have indepedent DAIF defaults.

Putting a big block of zeros in the kernel text just to initialise one
register seems overkill.  Now we're adding a third block of zeros,
maybe this is worth refactoring?  We really just need a memset(0)
followed by config-dependent initialisation of regs.pstate AFAICT.

Not a big deal though: this doesn't look like a high risk for
maintainability.

Cheers
---Dave

>  static const struct kvm_regs default_regs_reset32 = {
>   .regs.pstate = (PSR_AA32_MODE_SVC | PSR_AA32_A_BIT |
>   PSR_AA32_I_BIT | PSR_AA32_F_BIT),
> @@ -302,6 +307,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
>   if (!cpu_has_32bit_el1())
>   goto out;
>   cpu_reset = _regs_reset32;
> + } else if (test_bit(KVM_ARM_VCPU_NESTED_VIRT, 
> vcpu->arch.features)) {
> + cpu_reset = _regs_reset_el2;
>   } else {
>   cpu_reset = _regs_reset;
>   }
> -- 
> 2.20.1
> 
> 
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Re: [PATCH 05/59] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set

2019-06-24 Thread Suzuki K Poulose 




On 21/06/2019 10:37, Marc Zyngier wrote:

From: Christoffer Dall 

Reset the VCPU with PSTATE.M = EL2h when the nested virtualization
feature is enabled on the VCPU.

Signed-off-by: Christoffer Dall 
Signed-off-by: Marc Zyngier 
---
  arch/arm64/kvm/reset.c | 7 +++
  1 file changed, 7 insertions(+)

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 1140b4485575..675ca07dbb05 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -52,6 +52,11 @@ static const struct kvm_regs default_regs_reset = {
PSR_F_BIT | PSR_D_BIT),
  };
  
+static const struct kvm_regs default_regs_reset_el2 = {

+   .regs.pstate = (PSR_MODE_EL2h | PSR_A_BIT | PSR_I_BIT |
+   PSR_F_BIT | PSR_D_BIT),
+};
+
  static const struct kvm_regs default_regs_reset32 = {
.regs.pstate = (PSR_AA32_MODE_SVC | PSR_AA32_A_BIT |
PSR_AA32_I_BIT | PSR_AA32_F_BIT),
@@ -302,6 +307,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
if (!cpu_has_32bit_el1())
goto out;
cpu_reset = _regs_reset32;
+   } else if (test_bit(KVM_ARM_VCPU_NESTED_VIRT, 
vcpu->arch.features)) {


minor nit: "else if nested_virt_in_use(vcpu)" ?

Either ways:

Reviewed-by: Suzuki K Poulose 
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[PATCH 05/59] KVM: arm64: nv: Reset VCPU to EL2 registers if VCPU nested virt is set

2019-06-21 Thread Marc Zyngier 
From: Christoffer Dall 

Reset the VCPU with PSTATE.M = EL2h when the nested virtualization
feature is enabled on the VCPU.

Signed-off-by: Christoffer Dall 
Signed-off-by: Marc Zyngier 
---
 arch/arm64/kvm/reset.c | 7 +++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 1140b4485575..675ca07dbb05 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -52,6 +52,11 @@ static const struct kvm_regs default_regs_reset = {
PSR_F_BIT | PSR_D_BIT),
 };
 
+static const struct kvm_regs default_regs_reset_el2 = {
+   .regs.pstate = (PSR_MODE_EL2h | PSR_A_BIT | PSR_I_BIT |
+   PSR_F_BIT | PSR_D_BIT),
+};
+
 static const struct kvm_regs default_regs_reset32 = {
.regs.pstate = (PSR_AA32_MODE_SVC | PSR_AA32_A_BIT |
PSR_AA32_I_BIT | PSR_AA32_F_BIT),
@@ -302,6 +307,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
if (!cpu_has_32bit_el1())
goto out;
cpu_reset = _regs_reset32;
+   } else if (test_bit(KVM_ARM_VCPU_NESTED_VIRT, 
vcpu->arch.features)) {
+   cpu_reset = _regs_reset_el2;
} else {
cpu_reset = _regs_reset;
}
-- 
2.20.1

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