From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 63E5744471D for ; Mon, 20 Jul 2026 17:15:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784567735; cv=none; b=VoUN2DKvAcnmsgeKCehgnhIwc4m90iAALipkcdQDQJyc/j4n7SVHgIE+BvZ21T3CMCnA52x0hbVm59WUmLWWDzfp5+2qYP3AopuOTyhHU4cRuj5GPo17Qew56KpWs+P6TpsmpAoxk69LK5ygIAV83ToJBuYTEMaeboyqF8Eg/9M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784567735; c=relaxed/simple; bh=jrRio3n2o9F6x5hj91Ymetg8JMXzO0NlutaTPnp5k9I=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=A2/SyR+tt+MsKqG58Ap+TujdHSVtJQIXhhy6Xu0b+Ach1LUXnY4FUFYjKPFy8h+LIj+H49sum/yBKac/Vx2uLpw79B7WbAktH5X/JC0zmISCvPyPln5lMwDfaw3Ob0JfxxcsR6uR0wyom85XJ8rTR5GKRxeJRN2sNyhyXbmQePM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=W/sV9aKA; arc=none smtp.client-ip=209.85.221.70 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="W/sV9aKA" Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-47485fde05aso6123388f8f.0 for ; Mon, 20 Jul 2026 10:15:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1784567728; x=1785172528; darn=lists.linux.dev; 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=jN40ZfNJMy0FjY6srncII1llPxzne/Kt/F9K6awJPaQ=; b=W/sV9aKA3Pz1ufOjN+xoB1anJ/L8JOXGDD5XwRquIC4gYHyRdqtE/dA/qtlyErM8BN gmcHmjF5pao9/M6ICIycb+ixjLRsZyJ1W42EFiMperYuKo+jmz0U+myykC5LVABLNUjm o4R8FKNvdOgQiuiaR14Nx2Wo+Wc63Z0KBGFAMHHp9cykh8uWeJZwyRZ6nZSGpyVodIXX LWoe8KDS4gommViw2ZB7D5MfY9qq00Lx3ijnZhFUgo35ZgaRwhlqT/mO5SXFBhlLnF61 iReWcp8rXyRAQfNt3Qazj7E8c/71YN5WVREp8WRi22w4sr80ppPzVyFTEIFdYfxVQwhu JHNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784567728; x=1785172528; 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=jN40ZfNJMy0FjY6srncII1llPxzne/Kt/F9K6awJPaQ=; b=gb+ZYhDhknprE806NUYtsNpszELj899Yl08abZRtAJj8XnY1LDmJzN5R/tESQ1MjhJ JNN5ATYxSPCiP0ZyBSyICufCulW+GfSh/Ar3VaE6eUpBIop+3qJPaY4WfLZApEZ/nee2 NacRl8JtkFlqX+dFZ66KWeFLbIs0eBXZZJnLETWHGe6hRYq7BJXgJu/bytQI8nPGIIkh 51OlOMkWxF7CsPKXrJkIKUFWNUovQiB1X9jVhH8FJzdETr0RRvG6lS7Ssuf8xeYdfXwg qf5Fu7tUb/0pkGjMdIvNnGGR7aMJsljgH/YcrUGrBE+U1nL5IweAZtLBwBR2qH8giHdM fnyg== X-Forwarded-Encrypted: i=1; AHgh+Rr5lbKCSLqtfGQvRTzglaKJJ8G6wiTPM93nb/xTdmFrFLHy/dHFWMcUpJcc4q7Ta9+BntiBC0I=@lists.linux.dev X-Gm-Message-State: AOJu0Yx6qqnowPFCjNBENrhljf83WdGsd/NEHuCRrQQEWHtunsOXYL8V TmV5/1ROJ52g+7q7j4OuJ3Xd/vryd2x7vQZNCW/9ib+g9vf1g+pkCKdh8ftiknGK7Sv/EV+KDAV 4XyGqDZs/ixyxfGZxguigEA== X-Received: from wmhf19.prod.google.com ([2002:a7b:cc13:0:b0:493:bb29:af53]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:3515:b0:493:be13:98b with SMTP id 5b1f17b1804b1-4954a50c47emr162780435e9.23.1784567728133; Mon, 20 Jul 2026 10:15:28 -0700 (PDT) Date: Mon, 20 Jul 2026 18:15:04 +0100 In-Reply-To: <20260720171513.1415357-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260720171513.1415357-1-vdonnefort@google.com> X-Mailer: git-send-email 2.55.0.229.g6434b31f56-goog Message-ID: <20260720171513.1415357-9-vdonnefort@google.com> Subject: [PATCH v3 08/17] 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, tabba@google.com, qperret@google.com, Vincent Donnefort , Fuad Tabba Content-Type: text/plain; charset="UTF-8" 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 diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index b77acfd7d1c8..0c3126179704 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/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c index 439b91fc8aec..346365e76ef2 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c @@ -657,6 +657,42 @@ static void handle___pkvm_hyp_topup(struct kvm_cpu_context *host_ctxt) cpu_reg(host_ctxt, 3) = host_mc.nr_pages; } +static void handle___pkvm_hyp_reclaim(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(enum pkvm_topup_id, id, host_ctxt, 1); + DECLARE_REG(unsigned long, target, host_ctxt, 2); + 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, 1) = ret; + cpu_reg(host_ctxt, 2) = host_mc.head; + cpu_reg(host_ctxt, 3) = host_mc.nr_pages; +} + +static void handle___pkvm_hyp_reclaimable(struct kvm_cpu_context *host_ctxt) +{ + DECLARE_REG(enum pkvm_topup_id, id, host_ctxt, 1); + unsigned long reclaimable = 0; + + switch (id) { + case PKVM_TOPUP_HYP_ALLOC: + reclaimable = hyp_alloc_reclaimable(); + break; + default: + reclaimable = 0; + } + + cpu_reg(host_ctxt, 1) = reclaimable; +} + static void handle___tracing_load(struct kvm_cpu_context *host_ctxt) { DECLARE_REG(unsigned long, desc_hva, host_ctxt, 1); @@ -766,6 +802,8 @@ 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 d26e7435d34d..a82e773a1c2d 100644 --- a/arch/arm64/kvm/pkvm.c +++ b/arch/arm64/kvm/pkvm.c @@ -115,6 +115,29 @@ static int pkvm_hyp_topup(enum pkvm_topup_id id, unsigned long nr_pages) return ret; } +static __maybe_unused 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_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)) { -- 2.55.0.229.g6434b31f56-goog