From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965328AbcBCSAj (ORCPT ); Wed, 3 Feb 2016 13:00:39 -0500 Received: from foss.arm.com ([217.140.101.70]:36217 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965111AbcBCSAe (ORCPT ); Wed, 3 Feb 2016 13:00:34 -0500 From: Marc Zyngier To: Catalin Marinas , Will Deacon , Christoffer Dall Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Subject: [PATCH v3 07/23] arm64: KVM: VHE: Patch out use of HVC Date: Wed, 3 Feb 2016 18:00:00 +0000 Message-Id: <1454522416-6874-8-git-send-email-marc.zyngier@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1454522416-6874-1-git-send-email-marc.zyngier@arm.com> References: <1454522416-6874-1-git-send-email-marc.zyngier@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With VHE, the host never issues an HVC instruction to get into the KVM code, as we can simply branch there. Use runtime code patching to simplify things a bit. Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp.S | 7 +++++++ arch/arm64/kvm/hyp/hyp-entry.S | 40 +++++++++++++++++++++++++++++++--------- 2 files changed, 38 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S index 0ccdcbb..0689a74 100644 --- a/arch/arm64/kvm/hyp.S +++ b/arch/arm64/kvm/hyp.S @@ -17,7 +17,9 @@ #include +#include #include +#include /* * u64 kvm_call_hyp(void *hypfn, ...); @@ -38,6 +40,11 @@ * arch/arm64/kernel/hyp_stub.S. */ ENTRY(kvm_call_hyp) +alternative_if_not ARM64_HAS_VIRT_HOST_EXTN hvc #0 ret +alternative_else + b __vhe_hyp_call + nop +alternative_endif ENDPROC(kvm_call_hyp) diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S index 93e8d983..1bdeee7 100644 --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -38,6 +38,34 @@ ldp x0, x1, [sp], #16 .endm +.macro do_el2_call + /* + * Shuffle the parameters before calling the function + * pointed to in x0. Assumes parameters in x[1,2,3]. + */ + sub sp, sp, #16 + str lr, [sp] + mov lr, x0 + mov x0, x1 + mov x1, x2 + mov x2, x3 + blr lr + ldr lr, [sp] + add sp, sp, #16 +.endm + +ENTRY(__vhe_hyp_call) + do_el2_call + /* + * We used to rely on having an exception return to get + * an implicit isb. In the E2H case, we don't have it anymore. + * rather than changing all the leaf functions, just do it here + * before returning to the rest of the kernel. + */ + isb + ret +ENDPROC(__vhe_hyp_call) + el1_sync: // Guest trapped into EL2 save_x0_to_x3 @@ -58,19 +86,13 @@ el1_sync: // Guest trapped into EL2 mrs x0, vbar_el2 b 2f -1: stp lr, xzr, [sp, #-16]! - +1: /* - * Compute the function address in EL2, and shuffle the parameters. + * Perform the EL2 call */ kern_hyp_va x0 - mov lr, x0 - mov x0, x1 - mov x1, x2 - mov x2, x3 - blr lr + do_el2_call - ldp lr, xzr, [sp], #16 2: eret el1_trap: -- 2.1.4