From patchwork Thu Oct 27 22:23:11 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 13022917 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0AC20ECAAA1 for ; Thu, 27 Oct 2022 22:23:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235409AbiJ0WX0 (ORCPT ); Thu, 27 Oct 2022 18:23:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235376AbiJ0WXY (ORCPT ); Thu, 27 Oct 2022 18:23:24 -0400 Received: from out0.migadu.com (out0.migadu.com [94.23.1.103]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CFDCEA23E8 for ; Thu, 27 Oct 2022 15:23:22 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1666909401; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QDsaPTkBMVoCvpIbixNEzKkPpLmJ5PGsxu8t4GywA5c=; b=wYHQqf+dD0czI4mBZkyslR+ThYtCpgPd3GvtdhSqUuA0toNUVFKlGxD7Dhk1on/QapVGoL PiK+8XDZOuRvPQFfkmD1mkJKZPMyRgyU/PvUT0UQzqQYj3Ovy3pgx9F3txPwU3KIThN6yP 8AgDitEUCXh9tC9FoqFHQyfkX/rKmQ4= From: Oliver Upton To: Marc Zyngier , James Morse , Alexandru Elisei Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Reiji Watanabe , Ricardo Koller , David Matlack , Quentin Perret , Ben Gardon , Gavin Shan , Peter Xu , Will Deacon , Sean Christopherson , kvmarm@lists.linux.dev, Oliver Upton Subject: [PATCH v3 13/15] KVM: arm64: Make leaf->leaf PTE changes parallel-aware Date: Thu, 27 Oct 2022 22:23:11 +0000 Message-Id: <20221027222311.1685097-1-oliver.upton@linux.dev> In-Reply-To: <20221027221752.1683510-1-oliver.upton@linux.dev> References: <20221027221752.1683510-1-oliver.upton@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Convert stage2_map_walker_try_leaf() to use the new break-before-make helpers, thereby making the handler parallel-aware. As before, avoid the break-before-make if recreating the existing mapping. Additionally, retry execution if another vCPU thread is modifying the same PTE. Signed-off-by: Oliver Upton --- arch/arm64/kvm/hyp/pgtable.c | 26 ++++++++++++-------------- 1 file changed, 12 insertions(+), 14 deletions(-) diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 1df858c21b2e..581ba688c6f7 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -804,18 +804,17 @@ static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx, else new = kvm_init_invalid_leaf_owner(data->owner_id); - if (stage2_pte_is_counted(ctx->old)) { - /* - * Skip updating the PTE if we are trying to recreate the exact - * same mapping or only change the access permissions. Instead, - * the vCPU will exit one more time from guest if still needed - * and then go through the path of relaxing permissions. - */ - if (!stage2_pte_needs_update(ctx->old, new)) - return -EAGAIN; + /* + * Skip updating the PTE if we are trying to recreate the exact + * same mapping or only change the access permissions. Instead, + * the vCPU will exit one more time from guest if still needed + * and then go through the path of relaxing permissions. + */ + if (!stage2_pte_needs_update(ctx->old, new)) + return -EAGAIN; - stage2_put_pte(ctx, data->mmu, mm_ops); - } + if (!stage2_try_break_pte(ctx, data)) + return -EAGAIN; /* Perform CMOs before installation of the guest stage-2 PTE */ if (mm_ops->dcache_clean_inval_poc && stage2_pte_cacheable(pgt, new)) @@ -825,9 +824,8 @@ static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx, if (mm_ops->icache_inval_pou && stage2_pte_executable(new)) mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops), granule); - smp_store_release(ctx->ptep, new); - if (stage2_pte_is_counted(new)) - mm_ops->get_page(ctx->ptep); + stage2_make_pte(ctx, new); + if (kvm_phys_is_valid(phys)) data->phys += granule; return 0;