From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: Re: [PATCH v4 05/28] arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init code Date: Fri, 24 Mar 2017 14:45:24 +0000 Message-ID: References: <20170321192058.9300-1-marc.zyngier@arm.com> <20170321192058.9300-6-marc.zyngier@arm.com> <20170324143350.GB25903@cbox> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Russell King , kvm@vger.kernel.org, Ard Biesheuvel , Catalin Marinas , linux-arm-kernel@lists.infradead.org, Keerthy , kvmarm@lists.cs.columbia.edu To: Christoffer Dall Return-path: In-Reply-To: <20170324143350.GB25903@cbox> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu List-Id: kvm.vger.kernel.org On 24/03/17 14:33, Christoffer Dall wrote: > On Tue, Mar 21, 2017 at 07:20:35PM +0000, Marc Zyngier wrote: >> In order to restore HYP mode to its original condition, KVM currently >> implements __kvm_hyp_reset(). As we're moving towards a hyp-stub >> defined API, it becomes necessary to implement HVC_RESET_VECTORS. >> >> This patch adds the HVC_RESET_VECTORS hypercall to the KVM init >> code, which so far lacked any form of hypercall support. >> >> Reviewed-by: James Morse >> Signed-off-by: Marc Zyngier >> --- >> arch/arm64/kvm/hyp-init.S | 12 ++++++++++++ >> 1 file changed, 12 insertions(+) >> >> diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S >> index 6b29d3d9e1f2..6cf98ccd10f2 100644 >> --- a/arch/arm64/kvm/hyp-init.S >> +++ b/arch/arm64/kvm/hyp-init.S >> @@ -22,6 +22,7 @@ >> #include >> #include >> #include >> +#include >> >> .text >> .pushsection .hyp.idmap.text, "ax" >> @@ -58,6 +59,9 @@ __invalid: >> * x2: HYP vectors >> */ >> __do_hyp_init: >> + /* Check for a stub HVC call */ >> + cmp x0, #HVC_STUB_HCALL_NR >> + b.lo __kvm_handle_stub_hvc >> >> msr ttbr0_el2, x0 >> >> @@ -119,6 +123,9 @@ __do_hyp_init: >> eret >> ENDPROC(__kvm_hyp_init) >> >> +ENTRY(__kvm_handle_stub_hvc) >> + cmp x0, #HVC_RESET_VECTORS >> + b.ne 1f >> /* >> * Reset kvm back to the hyp stub. >> */ >> @@ -133,9 +140,14 @@ ENTRY(__kvm_hyp_reset) >> /* Install stub vectors */ >> adr_l x0, __hyp_stub_vectors >> msr vbar_el2, x0 >> + b exit >> >> +1: mov x0, #-1 > > nit: do we have the -1 return value documented somewhere and should we > define it as HVC_SUB_ERR_RETURN or something like that? Indeed, this is something that is a bit dodgy. arm64 returns ARM_EXCEPTION_HYP_GONE, which is really a KVM exception code (and isn't -1 either). I'll try to tighten this up a bit. Thanks, M. -- Jazz is not dead. It just smells funny... From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Fri, 24 Mar 2017 14:45:24 +0000 Subject: [PATCH v4 05/28] arm64: KVM: Implement HVC_RESET_VECTORS stub hypercall in the init code In-Reply-To: <20170324143350.GB25903@cbox> References: <20170321192058.9300-1-marc.zyngier@arm.com> <20170321192058.9300-6-marc.zyngier@arm.com> <20170324143350.GB25903@cbox> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 24/03/17 14:33, Christoffer Dall wrote: > On Tue, Mar 21, 2017 at 07:20:35PM +0000, Marc Zyngier wrote: >> In order to restore HYP mode to its original condition, KVM currently >> implements __kvm_hyp_reset(). As we're moving towards a hyp-stub >> defined API, it becomes necessary to implement HVC_RESET_VECTORS. >> >> This patch adds the HVC_RESET_VECTORS hypercall to the KVM init >> code, which so far lacked any form of hypercall support. >> >> Reviewed-by: James Morse >> Signed-off-by: Marc Zyngier >> --- >> arch/arm64/kvm/hyp-init.S | 12 ++++++++++++ >> 1 file changed, 12 insertions(+) >> >> diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S >> index 6b29d3d9e1f2..6cf98ccd10f2 100644 >> --- a/arch/arm64/kvm/hyp-init.S >> +++ b/arch/arm64/kvm/hyp-init.S >> @@ -22,6 +22,7 @@ >> #include >> #include >> #include >> +#include >> >> .text >> .pushsection .hyp.idmap.text, "ax" >> @@ -58,6 +59,9 @@ __invalid: >> * x2: HYP vectors >> */ >> __do_hyp_init: >> + /* Check for a stub HVC call */ >> + cmp x0, #HVC_STUB_HCALL_NR >> + b.lo __kvm_handle_stub_hvc >> >> msr ttbr0_el2, x0 >> >> @@ -119,6 +123,9 @@ __do_hyp_init: >> eret >> ENDPROC(__kvm_hyp_init) >> >> +ENTRY(__kvm_handle_stub_hvc) >> + cmp x0, #HVC_RESET_VECTORS >> + b.ne 1f >> /* >> * Reset kvm back to the hyp stub. >> */ >> @@ -133,9 +140,14 @@ ENTRY(__kvm_hyp_reset) >> /* Install stub vectors */ >> adr_l x0, __hyp_stub_vectors >> msr vbar_el2, x0 >> + b exit >> >> +1: mov x0, #-1 > > nit: do we have the -1 return value documented somewhere and should we > define it as HVC_SUB_ERR_RETURN or something like that? Indeed, this is something that is a bit dodgy. arm64 returns ARM_EXCEPTION_HYP_GONE, which is really a KVM exception code (and isn't -1 either). I'll try to tighten this up a bit. Thanks, M. -- Jazz is not dead. It just smells funny...