[PATCH v4 15/15] KVM: arm: enable trapping of all debug registers
Christoffer Dall
christoffer.dall at linaro.org
Wed Sep 2 09:08:14 PDT 2015
On Mon, Aug 10, 2015 at 09:26:07PM +0800, Zhichao Huang wrote:
> Enable trapping of the debug registers unconditionally, allowing guests to
> use the debug infrastructure.
>
> Signed-off-by: Zhichao Huang <zhichao.huang at linaro.org>
> Reviewed-by: Christoffer Dall <christoffer.dall at linaro.org>
> ---
> arch/arm/kvm/interrupts_head.S | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S
> index 7ad0adf..494991d 100644
> --- a/arch/arm/kvm/interrupts_head.S
> +++ b/arch/arm/kvm/interrupts_head.S
> @@ -792,7 +792,7 @@ ARM_BE8(rev r6, r6 )
> * (hardware reset value is 0) */
> .macro set_hdcr operation
> mrc p15, 4, r2, c1, c1, 1
> - ldr r3, =(HDCR_TPM|HDCR_TPMCR)
> + ldr r3, =(HDCR_TPM|HDCR_TPMCR|HDCR_TDRA|HDCR_TDOSA|HDCR_TDA)
eh, but I thought we didn't have to trap accesses to the debug registers
if we switch them, because the guest is likely to be using them?
Maybe I am getting confused, can you repeat for me exactly when we
context-switch the registers and when we trap accesses to them?
Thanks,
-Christoffer
> .if \operation == vmentry
> orr r2, r2, r3 @ Trap some perfmon accesses
> .else
> --
> 1.7.12.4
>
More information about the linux-arm-kernel
mailing list