2017-06-12 06:42:12

by Hu Huajun

[permalink] [raw]
Subject: [PATCH v2] KVM: ARM64: fix phy counter access failure in guest.

When reading the cntpct_el0 in guest with VHE (Virtual Host Extension)
enabled in host, the "Unsupported guest sys_reg access" error reported.
The reason is cnthctl_el2.EL1PCTEN is not enabled, which is expected
to be done in kvm_timer_init_vhe(). The problem is kvm_timer_init_vhe
is called by cpu_init_hyp_mode, and which is called when VHE is disabled.
This patch remove the incorrect call to kvm_timer_init_vhe() from
cpu_init_hyp_mode(), and calls kvm_timer_init_vhe() to enable
cnthctl_el2.EL1PCTEN in cpu_hyp_reinit().

Changes from v1:
* According to Christoffer Dall's comment, remove the incocrrect call
to kvm_timer_init_vhe() in cpu_init_hyp_mode().

Signed-off-by: Hu Huajun <[email protected]>
---
virt/kvm/arm/arm.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 3417e18..a430125 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -1115,9 +1115,6 @@ static void cpu_init_hyp_mode(void *dummy)
__cpu_init_hyp_mode(pgd_ptr, hyp_stack_ptr, vector_ptr);
__cpu_init_stage2();

- if (is_kernel_in_hyp_mode())
- kvm_timer_init_vhe();
-
kvm_arm_init_debug();
}

@@ -1137,6 +1134,7 @@ static void cpu_hyp_reinit(void)
* event was cancelled before the CPU was reset.
*/
__cpu_init_stage2();
+ kvm_timer_init_vhe();
} else {
cpu_init_hyp_mode(NULL);
}
--
2.10.1


2017-06-12 08:22:55

by Christoffer Dall

[permalink] [raw]
Subject: Re: [PATCH v2] KVM: ARM64: fix phy counter access failure in guest.

Hi,

On Mon, Jun 12, 2017 at 10:37:48PM +0800, Hu Huajun wrote:
> When reading the cntpct_el0 in guest with VHE (Virtual Host Extension)
> enabled in host, the "Unsupported guest sys_reg access" error reported.
> The reason is cnthctl_el2.EL1PCTEN is not enabled, which is expected
> to be done in kvm_timer_init_vhe(). The problem is kvm_timer_init_vhe
> is called by cpu_init_hyp_mode, and which is called when VHE is disabled.
> This patch remove the incorrect call to kvm_timer_init_vhe() from
> cpu_init_hyp_mode(), and calls kvm_timer_init_vhe() to enable
> cnthctl_el2.EL1PCTEN in cpu_hyp_reinit().
>
> Changes from v1:
> * According to Christoffer Dall's comment, remove the incocrrect call
> to kvm_timer_init_vhe() in cpu_init_hyp_mode().

In the future please put the changelog after the '---' delimeter,
because it doesn't have to be part of the commit log.

I can fix this up when applying though.

>
> Signed-off-by: Hu Huajun <[email protected]>

Reviewed-by: Christoffer Dall <[email protected]>

Applied.

Thanks,
-Christoffer

> ---
> virt/kvm/arm/arm.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index 3417e18..a430125 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -1115,9 +1115,6 @@ static void cpu_init_hyp_mode(void *dummy)
> __cpu_init_hyp_mode(pgd_ptr, hyp_stack_ptr, vector_ptr);
> __cpu_init_stage2();
>
> - if (is_kernel_in_hyp_mode())
> - kvm_timer_init_vhe();
> -
> kvm_arm_init_debug();
> }
>
> @@ -1137,6 +1134,7 @@ static void cpu_hyp_reinit(void)
> * event was cancelled before the CPU was reset.
> */
> __cpu_init_stage2();
> + kvm_timer_init_vhe();
> } else {
> cpu_init_hyp_mode(NULL);
> }
> --
> 2.10.1
>

2017-06-12 09:08:21

by Marc Zyngier

[permalink] [raw]
Subject: Re: [PATCH v2] KVM: ARM64: fix phy counter access failure in guest.

Nit: Please fix the time on your machine. It ended up in my Spam folder
because it comes from the future...

On 12/06/17 15:37, Hu Huajun wrote:
> When reading the cntpct_el0 in guest with VHE (Virtual Host Extension)
> enabled in host, the "Unsupported guest sys_reg access" error reported.
> The reason is cnthctl_el2.EL1PCTEN is not enabled, which is expected
> to be done in kvm_timer_init_vhe(). The problem is kvm_timer_init_vhe
> is called by cpu_init_hyp_mode, and which is called when VHE is disabled.
> This patch remove the incorrect call to kvm_timer_init_vhe() from
> cpu_init_hyp_mode(), and calls kvm_timer_init_vhe() to enable
> cnthctl_el2.EL1PCTEN in cpu_hyp_reinit().
>
> Changes from v1:
> * According to Christoffer Dall's comment, remove the incocrrect call
> to kvm_timer_init_vhe() in cpu_init_hyp_mode().
>
> Signed-off-by: Hu Huajun <[email protected]>
> ---
> virt/kvm/arm/arm.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index 3417e18..a430125 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -1115,9 +1115,6 @@ static void cpu_init_hyp_mode(void *dummy)
> __cpu_init_hyp_mode(pgd_ptr, hyp_stack_ptr, vector_ptr);
> __cpu_init_stage2();
>
> - if (is_kernel_in_hyp_mode())
> - kvm_timer_init_vhe();
> -
> kvm_arm_init_debug();
> }
>
> @@ -1137,6 +1134,7 @@ static void cpu_hyp_reinit(void)
> * event was cancelled before the CPU was reset.
> */
> __cpu_init_stage2();
> + kvm_timer_init_vhe();
> } else {
> cpu_init_hyp_mode(NULL);
> }
>

How about:

Cc: [email protected]
Fixes: 488f94d7212b ("KVM: arm64: Access CNTHCTL_EL2 bit fields
correctly on VHE systems")

Otherwise:

Acked-by: Marc Zyngier <[email protected]>

M.
--
Jazz is not dead. It just smells funny...

2017-06-12 09:20:04

by Christoffer Dall

[permalink] [raw]
Subject: Re: [PATCH v2] KVM: ARM64: fix phy counter access failure in guest.

On Mon, Jun 12, 2017 at 10:08:16AM +0100, Marc Zyngier wrote:
> Nit: Please fix the time on your machine. It ended up in my Spam folder
> because it comes from the future...
>
> On 12/06/17 15:37, Hu Huajun wrote:
> > When reading the cntpct_el0 in guest with VHE (Virtual Host Extension)
> > enabled in host, the "Unsupported guest sys_reg access" error reported.
> > The reason is cnthctl_el2.EL1PCTEN is not enabled, which is expected
> > to be done in kvm_timer_init_vhe(). The problem is kvm_timer_init_vhe
> > is called by cpu_init_hyp_mode, and which is called when VHE is disabled.
> > This patch remove the incorrect call to kvm_timer_init_vhe() from
> > cpu_init_hyp_mode(), and calls kvm_timer_init_vhe() to enable
> > cnthctl_el2.EL1PCTEN in cpu_hyp_reinit().
> >
> > Changes from v1:
> > * According to Christoffer Dall's comment, remove the incocrrect call
> > to kvm_timer_init_vhe() in cpu_init_hyp_mode().
> >
> > Signed-off-by: Hu Huajun <[email protected]>
> > ---
> > virt/kvm/arm/arm.c | 4 +---
> > 1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> > index 3417e18..a430125 100644
> > --- a/virt/kvm/arm/arm.c
> > +++ b/virt/kvm/arm/arm.c
> > @@ -1115,9 +1115,6 @@ static void cpu_init_hyp_mode(void *dummy)
> > __cpu_init_hyp_mode(pgd_ptr, hyp_stack_ptr, vector_ptr);
> > __cpu_init_stage2();
> >
> > - if (is_kernel_in_hyp_mode())
> > - kvm_timer_init_vhe();
> > -
> > kvm_arm_init_debug();
> > }
> >
> > @@ -1137,6 +1134,7 @@ static void cpu_hyp_reinit(void)
> > * event was cancelled before the CPU was reset.
> > */
> > __cpu_init_stage2();
> > + kvm_timer_init_vhe();
> > } else {
> > cpu_init_hyp_mode(NULL);
> > }
> >
>
> How about:
>
> Cc: [email protected]
> Fixes: 488f94d7212b ("KVM: arm64: Access CNTHCTL_EL2 bit fields
> correctly on VHE systems")

Yes, definitely. I've added this.

>
> Otherwise:
>
> Acked-by: Marc Zyngier <[email protected]>
>

Thanks,
-Christoffer