From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4C6D7CA5FD4 for ; Thu, 1 Oct 2026 15:51:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:Cc:To:From: Subject:Message-ID:References:Mime-Version:In-Reply-To:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=4T99T3TB8dvRshTDEDVSJZNJ9yGL6DvbnmzYOdgUiRk=; b=FD5bBC1y/ZaBWiJIEPcp0bST2h l5DFEv0sT0yXRGGHSpUoz4FNVT05EbbUdrfBhyHpIOggovuwF1jv4Se81UAxGdhp7rjX3br2AWELQ FV7QEnGm7xPA+3SBT2XoDH69iVlWU3fJANri0IPRISmWIHqbcNmhOycxiBkEd5EqZ/mHZjtXnuWqY dtCS1FOwVFJzpWYmqqZqmDph39fCNqRPQ+nhSyP6JPc1E9Njk4BqIP7Im66MPZnZja8tM+vkcBD7G j+k3lGk60E9ZT6tI9pgheCoOXRg75ZQn1MYmy/UkB4EROu2p7xYZRkz4AaYGjAolhLVg5D6cm7n4+ XQUl8H9A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xCHmd-00000009NLy-1DZR; Thu, 01 Oct 2026 14:29:15 +0000 Received: from mail-wm1-x346.google.com ([2a00:1450:4864:20::346]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1xCHmX-00000009NCV-2LrF for linux-arm-kernel@lists.infradead.org; Thu, 01 Oct 2026 14:29:11 +0000 Received: by mail-wm1-x346.google.com with SMTP id 5b1f17b1804b1-4a01eb045feso10659375e9.1 for ; Thu, 01 Oct 2026 07:29:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1790864947; x=1791469747; darn=lists.infradead.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=4T99T3TB8dvRshTDEDVSJZNJ9yGL6DvbnmzYOdgUiRk=; b=dRafnRq7cY3pKiJ3AQ8Q2rawL1Hhz3DU3253QWLSnUnx/Sw38Iwvc/M4nAY+x0pUZL 2c/g8pcQ/tIhP+pw+kJ9lXxA0kZPZ5sWr7SccYkaFvNW8q+wFjsoiXOeT5w7atUFFbdt Jf3dhEmy+4A5LAdfKabmQqqKZcCD2y4dJHI83a3J0tut+6pKt1VKyB1V3pOaKZA7KT8k 4UOrzzDgwPsz4pPCAv3NsFZFzbuTeBQf0h3C9ubH/Tk8aJZNaCS/2QBKKVl8P4DT4a+F TGzm3/zOVUXGykryRB3R3an5NH25PPYcLD7qJij5k3eK51Mtcu8B3+aECyE2FNs0GiEp C60A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790864947; x=1791469747; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=4T99T3TB8dvRshTDEDVSJZNJ9yGL6DvbnmzYOdgUiRk=; b=r1/Y8NzqkPYKH24KQbi9Dn7Hmt47oUG2K9+eaeDj82g60wh4xUhK8wo0Ojq5qY/iUH wX89VtEZxg1Fr2hkvNhDXIvGE9VkfjZxd7ePkWkqG0qG4qJLxCupc5nKvZqpdKj6quik +Eo9j7NGW8ErqepL6fRSM926wqLtOOswCWieO2QW9pUygC6953XzAXJXwbTjQ+MkK5vK l3M8az7oczm1YPSLgxhxrjElUvqLMy0Hod+oEqIaQzo8iwXKl/W42rQZ/4gi6rHjtyj4 N8yxk+qlUElrNcyzsvmLkt8/vMcp97g7rrnZYx3+VHCZQ4CXqir0ENtwxUMbIHjkBQVw cIjA== X-Forwarded-Encrypted: i=1; AKwUvBzYXLicEEPToddN38lW9LnU6W4kAEh9t8BANDgevl78W71bn3zjV3YuH9pNrahuXZGUSc/v5Vrb40Z7gUYmVKTW@lists.infradead.org X-Gm-Message-State: AFuF++mTgBymczU2o+pro+4xT8jhYjbK9AfVp1NiK7WF7CSEf31h/hdR xe0bRs4xgny9vFWuCsfMOetGcrXcv84BdZwaZoD5dEvLEcNgPV9kT3MM+vPKiR4KfBFuxwJsfFA OgQ0SzZGDOxGUAUg1xhZquQ== X-Received: from wmer17.prod.google.com ([2002:a05:600c:4351:b0:4a0:1efb:4825]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600d:6405:20b0:4a0:1b14:d00c with SMTP id 5b1f17b1804b1-4a01b14d05dmr62965735e9.3.1790864946825; Thu, 01 Oct 2026 07:29:06 -0700 (PDT) Date: Thu, 1 Oct 2026 15:28:39 +0100 In-Reply-To: <20261001142849.3367614-1-vdonnefort@google.com> Mime-Version: 1.0 References: <20261001142849.3367614-1-vdonnefort@google.com> X-Mailer: git-send-email 2.56.0.rc1.315.gc6ed9934b7-goog Message-ID: <20261001142849.3367614-9-vdonnefort@google.com> Subject: [PATCH v6 08/18] KVM: arm64: Add reclaim interface for the pKVM heap alloc From: Vincent Donnefort To: maz@kernel.org, oupton@kernel.org, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org Cc: joey.gouly@arm.com, seiden@linux.ibm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, kernel-team@android.com, fuad.tabba@linux.dev, Vincent Donnefort Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261001_072909_628795_AB6E712F X-CRM114-Status: GOOD ( 16.08 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Introduce a host interface to reclaim donated memory from the pKVM heap allocator back to the host. It specifically provides two helpers that will make it easier to create a shrinker for pKVM: pkvm_hyp_reclaimable() pkvm_hyp_relaim() Signed-off-by: Vincent Donnefort Reviewed-by: Fuad Tabba Tested-by: Fuad Tabba --- arch/arm64/include/asm/kvm_asm.h | 2 ++ arch/arm64/include/asm/kvm_hcall.h | 4 +++ arch/arm64/kvm/hyp/nvhe/hyp-main.c | 34 +++++++++++++++++++++++ arch/arm64/kvm/pkvm.c | 44 ++++++++++++++++++++++++++++++ 4 files changed, 84 insertions(+) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index de59e89318fa..fc3c52b03154 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -90,6 +90,8 @@ enum __kvm_host_smccc_func { __KVM_HOST_SMCCC_FUNC___vgic_v5_save_apr, __KVM_HOST_SMCCC_FUNC___vgic_v5_restore_vmcr_apr, __KVM_HOST_SMCCC_FUNC___pkvm_hyp_topup, + __KVM_HOST_SMCCC_FUNC___pkvm_hyp_reclaim, + __KVM_HOST_SMCCC_FUNC___pkvm_hyp_reclaimable, MARKER(__KVM_HOST_SMCCC_FUNC_PKVM_ONLY), diff --git a/arch/arm64/include/asm/kvm_hcall.h b/arch/arm64/include/asm/kvm_hcall.h index 6d6f12400e94..bce6eb8b20e0 100644 --- a/arch/arm64/include/asm/kvm_hcall.h +++ b/arch/arm64/include/asm/kvm_hcall.h @@ -199,6 +199,10 @@ DECLARE_KVM_HOST_HCALL(void, __vgic_v5_restore_vmcr_apr, struct vgic_v5_cpu_if __kern *, cpu_if) DECLARE_KVM_HOST_HCALL(int, __pkvm_hyp_topup, enum pkvm_topup_id, id, phys_addr_t, head, unsigned long, nr_pages) +DECLARE_KVM_HOST_HCALL(int, __pkvm_hyp_reclaim, + enum pkvm_topup_id, id, unsigned long, target) +DECLARE_KVM_HOST_HCALL(ulong, __pkvm_hyp_reclaimable, + enum pkvm_topup_id, id) /* Hypercalls that are available only when pKVM has finalised. */ DECLARE_KVM_HOST_HCALL(int, __pkvm_host_share_hyp, diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 2b89eb274482..fdc39f064718 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -824,6 +824,38 @@ DEFINE_KVM_HOST_HCALL(int, __pkvm_hyp_topup, return ret; } +DEFINE_KVM_HOST_HCALL(int, __pkvm_hyp_reclaim, + enum pkvm_topup_id, id, unsigned long, target) +{ + struct kvm_cpu_context *host_ctxt = host_data_ptr(host_ctxt); + struct kvm_hyp_memcache host_mc = {}; + int ret = 0; + + switch (id) { + case PKVM_TOPUP_HYP_ALLOC: + hyp_alloc_reclaim(&host_mc, target); + break; + default: + ret = -EINVAL; + } + + cpu_reg(host_ctxt, 2) = host_mc.head; + cpu_reg(host_ctxt, 3) = host_mc.nr_pages; + + return ret; +} + +DEFINE_KVM_HOST_HCALL(ulong, __pkvm_hyp_reclaimable, + enum pkvm_topup_id, id) +{ + switch (id) { + case PKVM_TOPUP_HYP_ALLOC: + return hyp_alloc_reclaimable(); + default: + return 0; + } +} + DEFINE_KVM_HOST_HCALL(int, __tracing_load, void __kern *, desc_hva, size_t, desc_size) { @@ -919,6 +951,8 @@ static const hcall_t host_hcall[] = { HANDLE_FUNC(__vgic_v5_save_apr), HANDLE_FUNC(__vgic_v5_restore_vmcr_apr), HANDLE_FUNC(__pkvm_hyp_topup), + HANDLE_FUNC(__pkvm_hyp_reclaim), + HANDLE_FUNC(__pkvm_hyp_reclaimable), HANDLE_FUNC(__pkvm_host_share_hyp), HANDLE_FUNC(__pkvm_host_unshare_hyp), diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c index 9cd23978481c..fec819a9dc78 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -115,6 +115,50 @@ static int pkvm_hyp_topup(enum pkvm_topup_id id, unsigned long nr_pages) return ret; } +static unsigned long __pkvm_hyp_reclaim(enum pkvm_topup_id id, unsigned long target) +{ + struct kvm_hyp_memcache mc; + struct arm_smccc_res res; + unsigned long reclaimed; + + arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(__pkvm_hyp_reclaim), id, target, &res); + if (WARN_ON_ONCE(res.a0 != SMCCC_RET_SUCCESS) || WARN_ON_ONCE(res.a1)) + return 0; + + init_hyp_memcache(&mc); + mc.head = res.a2; + mc.nr_pages = reclaimed = res.a3; + free_hyp_memcache(&mc); + + return reclaimed; +} + +static __maybe_unused unsigned long pkvm_hyp_reclaim(enum pkvm_topup_id id, unsigned long target) +{ + unsigned long reclaimed = 0; + + while (reclaimed < target) { + /* Arbitrary limit to avoid blocking in EL2 for too long */ + unsigned long r = __pkvm_hyp_reclaim(id, min(target - reclaimed, 16)); + + if (!r) + break; + + reclaimed += r; + if (reclaimed >= target) + break; + + cond_resched(); + } + + return reclaimed; +} + +static __maybe_unused unsigned long pkvm_hyp_reclaimable(enum pkvm_topup_id id) +{ + return kvm_call_hyp_nvhe(__pkvm_hyp_reclaimable, id); +} + static void __pkvm_destroy_hyp_vm(struct kvm *kvm) { if (pkvm_hyp_vm_is_created(kvm)) { -- 2.56.0.rc1.315.gc6ed9934b7-goog