From patchwork Fri Jan 6 01:32:49 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: James Hogan X-Patchwork-Id: 9499867 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 66841606DE for ; Fri, 6 Jan 2017 01:35:25 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5776D2848A for ; Fri, 6 Jan 2017 01:35:25 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4A82D28496; Fri, 6 Jan 2017 01:35:25 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B68A12848A for ; Fri, 6 Jan 2017 01:35:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752430AbdAFBfW (ORCPT ); Thu, 5 Jan 2017 20:35:22 -0500 Received: from mailapp01.imgtec.com ([195.59.15.196]:1466 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752331AbdAFBen (ORCPT ); Thu, 5 Jan 2017 20:34:43 -0500 Received: from HHMAIL01.hh.imgtec.org (unknown [10.100.10.19]) by Forcepoint Email with ESMTPS id DEFD9146509DD; Fri, 6 Jan 2017 01:33:40 +0000 (GMT) Received: from jhogan-linux.le.imgtec.org (192.168.154.110) by HHMAIL01.hh.imgtec.org (10.100.10.21) with Microsoft SMTP Server (TLS) id 14.3.294.0; Fri, 6 Jan 2017 01:33:41 +0000 From: James Hogan To: CC: James Hogan , Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Ralf Baechle , Subject: [PATCH 17/30] KVM: MIPS: Add fast path TLB refill handler Date: Fri, 6 Jan 2017 01:32:49 +0000 Message-ID: X-Mailer: git-send-email 2.11.0 MIME-Version: 1.0 In-Reply-To: References: X-Originating-IP: [192.168.154.110] Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Use functions from the general MIPS TLB exception vector generation code (tlbex.c) to construct a fast path TLB refill handler similar to the general one, but cut down and capable of preserving K0 and K1. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: "Radim Krčmář" Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org --- arch/mips/include/asm/kvm_host.h | 1 +- arch/mips/kvm/entry.c | 78 +++++++++++++++++++++++++++++++++- arch/mips/kvm/mips.c | 8 +-- 3 files changed, 84 insertions(+), 3 deletions(-) diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h index 8c4a33e9687d..7bf8ee8bc01d 100644 --- a/arch/mips/include/asm/kvm_host.h +++ b/arch/mips/include/asm/kvm_host.h @@ -554,6 +554,7 @@ extern int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu); /* Building of entry/exception code */ int kvm_mips_entry_setup(void); void *kvm_mips_build_vcpu_run(void *addr); +void *kvm_mips_build_tlb_refill_exception(void *addr, void *handler); void *kvm_mips_build_exception(void *addr, void *handler); void *kvm_mips_build_exit(void *addr); diff --git a/arch/mips/kvm/entry.c b/arch/mips/kvm/entry.c index 7424d3d566ff..1ae33e0e675c 100644 --- a/arch/mips/kvm/entry.c +++ b/arch/mips/kvm/entry.c @@ -16,6 +16,7 @@ #include #include #include +#include #include /* Register names */ @@ -122,6 +123,9 @@ int kvm_mips_entry_setup(void) */ unsigned int kscratch_mask = cpu_data[0].kscratch_mask; + if (pgd_reg != -1) + kscratch_mask &= ~BIT(pgd_reg); + /* Pick a scratch register for storing VCPU */ if (kscratch_mask) { scratch_vcpu[0] = c0_kscratch(); @@ -381,6 +385,80 @@ static void *kvm_mips_build_enter_guest(void *addr) } /** + * kvm_mips_build_tlb_refill_exception() - Assemble TLB refill handler. + * @addr: Address to start writing code. + * @handler: Address of common handler (within range of @addr). + * + * Assemble TLB refill exception fast path handler for guest execution. + * + * Returns: Next address after end of written function. + */ +void *kvm_mips_build_tlb_refill_exception(void *addr, void *handler) +{ + u32 *p = addr; + struct uasm_label labels[2]; + struct uasm_reloc relocs[2]; + struct uasm_label *l = labels; + struct uasm_reloc *r = relocs; + + memset(labels, 0, sizeof(labels)); + memset(relocs, 0, sizeof(relocs)); + + /* Save guest k1 into scratch register */ + UASM_i_MTC0(&p, K1, scratch_tmp[0], scratch_tmp[1]); + + /* Get the VCPU pointer from the VCPU scratch register */ + UASM_i_MFC0(&p, K1, scratch_vcpu[0], scratch_vcpu[1]); + + /* Save guest k0 into VCPU structure */ + UASM_i_SW(&p, K0, offsetof(struct kvm_vcpu, arch.gprs[K0]), K1); + + /* + * Some of the common tlbex code uses current_cpu_type(). For KVM we + * assume symmetry and just disable preemption to silence the warning. + */ + preempt_disable(); + + /* + * Now for the actual refill bit. A lot of this can be common with the + * Linux TLB refill handler, however we don't need to handle so many + * cases. We only need to handle user mode refills, and user mode runs + * with 32-bit addressing. + * + * Therefore the branch to label_vmalloc generated by build_get_pmde64() + * that isn't resolved should never actually get taken and is harmless + * to leave in place for now. + */ + +#ifdef CONFIG_64BIT + build_get_pmde64(&p, &l, &r, K0, K1); /* get pmd in K1 */ +#else + build_get_pgde32(&p, K0, K1); /* get pgd in K1 */ +#endif + + /* we don't support huge pages yet */ + + build_get_ptep(&p, K0, K1); + build_update_entries(&p, K0, K1); + build_tlb_write_entry(&p, &l, &r, tlb_random); + + preempt_enable(); + + /* Get the VCPU pointer from the VCPU scratch register again */ + UASM_i_MFC0(&p, K1, scratch_vcpu[0], scratch_vcpu[1]); + + /* Restore the guest's k0/k1 registers */ + UASM_i_LW(&p, K0, offsetof(struct kvm_vcpu, arch.gprs[K0]), K1); + uasm_i_ehb(&p); + UASM_i_MFC0(&p, K1, scratch_tmp[0], scratch_tmp[1]); + + /* Jump to guest */ + uasm_i_eret(&p); + + return p; +} + +/** * kvm_mips_build_exception() - Assemble first level guest exception handler. * @addr: Address to start writing code. * @handler: Address of common handler (within range of @addr). diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index 39792ec73a6d..3cf720790ce6 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -264,7 +264,7 @@ static inline void dump_handler(const char *symbol, void *start, void *end) struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id) { int err, size; - void *gebase, *p, *handler; + void *gebase, *p, *handler, *refill_start, *refill_end; int i; struct kvm_vcpu *vcpu = kzalloc(sizeof(struct kvm_vcpu), GFP_KERNEL); @@ -317,8 +317,9 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id) /* Build guest exception vectors dynamically in unmapped memory */ handler = gebase + 0x2000; - /* TLB Refill, EXL = 0 */ - kvm_mips_build_exception(gebase, handler); + /* TLB refill */ + refill_start = gebase; + refill_end = kvm_mips_build_tlb_refill_exception(refill_start, handler); /* General Exception Entry point */ kvm_mips_build_exception(gebase + 0x180, handler); @@ -344,6 +345,7 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id) pr_debug("#include \n"); pr_debug("\n"); dump_handler("kvm_vcpu_run", vcpu->arch.vcpu_run, p); + dump_handler("kvm_tlb_refill", refill_start, refill_end); dump_handler("kvm_gen_exc", gebase + 0x180, gebase + 0x200); dump_handler("kvm_exit", gebase + 0x2000, vcpu->arch.vcpu_run);