From mboxrd@z Thu Jan 1 00:00:00 1970 From: christoffer.dall@linaro.org (Christoffer Dall) Date: Wed, 2 Sep 2015 18:08:14 +0200 Subject: [PATCH v4 15/15] KVM: arm: enable trapping of all debug registers In-Reply-To: <1439213167-8988-16-git-send-email-zhichao.huang@linaro.org> References: <1439213167-8988-1-git-send-email-zhichao.huang@linaro.org> <1439213167-8988-16-git-send-email-zhichao.huang@linaro.org> Message-ID: <20150902160814.GS10991@cbox> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 > Reviewed-by: Christoffer Dall > --- > 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 >