diff mbox series

[08/59] KVM: arm64: nv: Reset VMPIDR_EL2 and VPIDR_EL2 to sane values

Message ID 20190621093843.220980-9-marc.zyngier@arm.com (mailing list archive)
State New, archived
Headers show
Series KVM: arm64: ARMv8.3 Nested Virtualization support | expand

Commit Message

Marc Zyngier June 21, 2019, 9:37 a.m. UTC 
The VMPIDR_EL2 and VPIDR_EL2 are architecturally UNKNOWN at reset, but
let's be nice to a guest hypervisor behaving foolishly and reset these
to something reasonable anyway.

Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/kvm/sys_regs.c | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

Comments

Dave Martin June 24, 2019, 12:59 p.m. UTC | #1 
On Fri, Jun 21, 2019 at 10:37:52AM +0100, Marc Zyngier wrote:
> The VMPIDR_EL2 and VPIDR_EL2 are architecturally UNKNOWN at reset, but
> let's be nice to a guest hypervisor behaving foolishly and reset these
> to something reasonable anyway.

Why be nice?  Generally we do try to initialise UNKNOWN regs to garbage,
to help trip up badly-written guests.

Cheers
---Dave

> 
> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm64/kvm/sys_regs.c | 25 +++++++++++++++++++++----
>  1 file changed, 21 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index e81be6debe07..693dd063c9c2 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -624,7 +624,7 @@ static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
>  	vcpu_write_sys_reg(vcpu, amair, AMAIR_EL1);
>  }
>  
> -static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +static u64 compute_reset_mpidr(struct kvm_vcpu *vcpu)
>  {
>  	u64 mpidr;
>  
> @@ -638,7 +638,24 @@ static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
>  	mpidr = (vcpu->vcpu_id & 0x0f) << MPIDR_LEVEL_SHIFT(0);
>  	mpidr |= ((vcpu->vcpu_id >> 4) & 0xff) << MPIDR_LEVEL_SHIFT(1);
>  	mpidr |= ((vcpu->vcpu_id >> 12) & 0xff) << MPIDR_LEVEL_SHIFT(2);
> -	vcpu_write_sys_reg(vcpu, (1ULL << 31) | mpidr, MPIDR_EL1);
> +	mpidr |= (1ULL << 31);
> +
> +	return mpidr;
> +}
> +
> +static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +{
> +	vcpu_write_sys_reg(vcpu, compute_reset_mpidr(vcpu), MPIDR_EL1);
> +}
> +
> +static void reset_vmpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +{
> +	vcpu_write_sys_reg(vcpu, compute_reset_mpidr(vcpu), VMPIDR_EL2);
> +}
> +
> +static void reset_vpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> +{
> +	vcpu_write_sys_reg(vcpu, read_cpuid_id(), VPIDR_EL2);
>  }
>  
>  static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
> @@ -1668,8 +1685,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
>  	 */
>  	{ SYS_DESC(SYS_PMCCFILTR_EL0), access_pmu_evtyper, reset_val, PMCCFILTR_EL0, 0 },
>  
> -	{ SYS_DESC(SYS_VPIDR_EL2), access_rw, reset_val, VPIDR_EL2, 0 },
> -	{ SYS_DESC(SYS_VMPIDR_EL2), access_rw, reset_val, VMPIDR_EL2, 0 },
> +	{ SYS_DESC(SYS_VPIDR_EL2), access_rw, reset_vpidr, VPIDR_EL2 },
> +	{ SYS_DESC(SYS_VMPIDR_EL2), access_rw, reset_vmpidr, VMPIDR_EL2 },
>  
>  	{ SYS_DESC(SYS_SCTLR_EL2), access_rw, reset_val, SCTLR_EL2, 0 },
>  	{ SYS_DESC(SYS_ACTLR_EL2), access_rw, reset_val, ACTLR_EL2, 0 },
> -- 
> 2.20.1
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
diff mbox series

Patch

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index e81be6debe07..693dd063c9c2 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -624,7 +624,7 @@  static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 	vcpu_write_sys_reg(vcpu, amair, AMAIR_EL1);
 }
 
-static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static u64 compute_reset_mpidr(struct kvm_vcpu *vcpu)
 {
 	u64 mpidr;
 
@@ -638,7 +638,24 @@  static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 	mpidr = (vcpu->vcpu_id & 0x0f) << MPIDR_LEVEL_SHIFT(0);
 	mpidr |= ((vcpu->vcpu_id >> 4) & 0xff) << MPIDR_LEVEL_SHIFT(1);
 	mpidr |= ((vcpu->vcpu_id >> 12) & 0xff) << MPIDR_LEVEL_SHIFT(2);
-	vcpu_write_sys_reg(vcpu, (1ULL << 31) | mpidr, MPIDR_EL1);
+	mpidr |= (1ULL << 31);
+
+	return mpidr;
+}
+
+static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+{
+	vcpu_write_sys_reg(vcpu, compute_reset_mpidr(vcpu), MPIDR_EL1);
+}
+
+static void reset_vmpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+{
+	vcpu_write_sys_reg(vcpu, compute_reset_mpidr(vcpu), VMPIDR_EL2);
+}
+
+static void reset_vpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+{
+	vcpu_write_sys_reg(vcpu, read_cpuid_id(), VPIDR_EL2);
 }
 
 static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
@@ -1668,8 +1685,8 @@  static const struct sys_reg_desc sys_reg_descs[] = {
 	 */
 	{ SYS_DESC(SYS_PMCCFILTR_EL0), access_pmu_evtyper, reset_val, PMCCFILTR_EL0, 0 },
 
-	{ SYS_DESC(SYS_VPIDR_EL2), access_rw, reset_val, VPIDR_EL2, 0 },
-	{ SYS_DESC(SYS_VMPIDR_EL2), access_rw, reset_val, VMPIDR_EL2, 0 },
+	{ SYS_DESC(SYS_VPIDR_EL2), access_rw, reset_vpidr, VPIDR_EL2 },
+	{ SYS_DESC(SYS_VMPIDR_EL2), access_rw, reset_vmpidr, VMPIDR_EL2 },
 
 	{ SYS_DESC(SYS_SCTLR_EL2), access_rw, reset_val, SCTLR_EL2, 0 },
 	{ SYS_DESC(SYS_ACTLR_EL2), access_rw, reset_val, ACTLR_EL2, 0 },