From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) (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 9001A49C4AE for ; Thu, 1 Oct 2026 20:22:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790886174; cv=none; b=Bstrn6k5UByaud92IpHmmQvnmJWE8ZsGIb7R1YD+d3YsuE3MfIWI3fWmkazJPEho07S8XxF+kdANMV6TDgrqPUtHVEFm3mnbHU4Z1Xd3dS585BpRtD2S6zZyUQzPH8qQQnVvq91rr+vwebXs5UevE4K8XarkM7MHseyzmaN3kRM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790886174; c=relaxed/simple; bh=WQb40a97ROmFqjiNKo3SgQ6E9gFV/eXSZB9E31DVrDc=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=tNHTLJzxPOds1hMDfifMT+2MbH+q0gR9XjGqRqneq2c+f8H+UbUbNA9TNN8piejJ86LLao+xOcn8vAVAdNWqj1WEPHi9vMPE6T6q0XvRTCtpPALXxLe0PePspMLoabDN1f002Ox0Uq1mqL45iW2q/jtq7tHpqyDX4tPQnWZL1yg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=rnm2qkZw; arc=none smtp.client-ip=209.85.210.199 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--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="rnm2qkZw" Received: by mail-pf1-f199.google.com with SMTP id d2e1a72fcca58-8886b1d3242so902658b3a.0 for ; Thu, 01 Oct 2026 13:22:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1790886165; x=1791490965; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:from:to:cc:subject:date:message-id :reply-to:content-type; bh=ymfeYEmvW6bR4RRG+DI7t0UxyoSVGW7KhY3QEGj26Qs=; b=rnm2qkZwyBUnuFV7gtS7IXRTF7/uISYRwqSkKXhcLoDZ+XOV2elUa84mUc5ZkdOvZ1 KvUJJCZixg7+PWuAYXrsURqlb6F2gYRkVDHckWi3NCMhnKVFelHnxHkYaMgVpMDCY+hX C/5bgNPm8epVKPUBFLnm7wGpU2d/6SfC0lb1WNlNki0TGNpbhnT93fbz38i2KjLJW61I zR+VjqVR4dYlGQwOI+YfQ3MunkiJlE3E7xSNN56cs0k8/9ECIa75s+dPfIqvj4jfQ74k 0cq1hGnvsqmJN2eirshf5dkt+dxEJaAwyW59ANuF765oh2CaLd9cK5Zm33pUBFT2Pfnr GBHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790886165; x=1791490965; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:reply-to:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to:content-type; bh=ymfeYEmvW6bR4RRG+DI7t0UxyoSVGW7KhY3QEGj26Qs=; b=OYxH2GexVuPhgPT4MapsJk+9AkadeQLZ2i6FwIEqm2DtyrURkS6BC8M08zh/L5rv7+ PNFwDPKeV7FRSjtWEHJ5C3MFe7ukoat8uNRRFIuB+t71tdlhzjuB6JTICA3RASPLSAJM MiuGUMut6G8WO4jh8cPn01MmRe+H/OpwrMc34VhhCghP2UauvuUXLHiZSiA7LnAFWGJ1 z52sRs09bb0karRGIbeXvpTmlKlUSc5DV5ePiZpOifVpnzqvCu3kuGqkPO6o3AwLvgQk 8yOYWjAnPv65AOb8aFH8CQu1PHa774yWzhFpKfDaehrczkWXBnfQ/qRyJv+2g6/4T6aZ F7aw== X-Forwarded-Encrypted: i=1; AKwUvBxPERRpdrbxzlctZWFAo+78zvP8wsExMDEceOwlVUUJVYKhcalvuLgiKqD+pRqZAxGQv9E=@vger.kernel.org X-Gm-Message-State: AFuF++nV7aMvH1e6is6hhHdXhWMwMJqhPezyFZ0hkIXf2H4kJBvBb46e qaG1BpFxFApXqsaHDkexhK9hdC/aHYTYy6XLa7vSQ6mmOjOvfxirs4iEswC8wOFthZ4sYco4BvU tsA32JA== X-Received: from pgbfq17.prod.google.com ([2002:a05:6a02:2991:b0:cc7:9b89:2a72]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:a518:b0:3d3:ae40:51e5 with SMTP id adf61e73a8af0-3e0bcf27ea4mr485150637.25.1790886165277; Thu, 01 Oct 2026 13:22:45 -0700 (PDT) Reply-To: Sean Christopherson Date: Thu, 1 Oct 2026 13:22:27 -0700 In-Reply-To: <20261001202234.3794060-1-seanjc@google.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20261001202234.3794060-1-seanjc@google.com> X-Mailer: git-send-email 2.56.0.rc1.315.gc6ed9934b7-goog Message-ID: <20261001202234.3794060-4-seanjc@google.com> Subject: [PATCH v2 03/10] KVM: x86: Unmap VMAs for KVM-internal memslots when the memslot is freed From: Sean Christopherson To: Madhavan Srinivasan , Sean Christopherson , Paolo Bonzini Cc: Nicholas Piggin , linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Jim Mattson Content-Type: text/plain; charset="UTF-8" Unmap KVM-created VMAs for KVM-internal memslots when the associated memslot is freed instead of unmapping via x86's internal API. This will allow deleting/freeing all memslots before kvm_arch_destroy_vm() without leaking VMAs, and in general is a net positive as it makes it far less likely that KVM will leak VMAs, e.g. in the unlikely scenario some other flow deletes KVM-internal memslots without going through __x86_set_memory_region(). Signed-off-by: Sean Christopherson --- arch/x86/kvm/x86.c | 36 ++++++++++++++---------------------- 1 file changed, 14 insertions(+), 22 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 79468ddfe473..e91bd79dd3cc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9925,7 +9925,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) * @size > 0 to install a new slot, while @size == 0 to uninstall a * slot. The return code can be one of the following: * - * HVA: on success (uninstall will return a bogus HVA) + * HVA: on success (uninstall will return a NULL HVA) * -errno: on error * * The caller should always use IS_ERR() to check the return value @@ -9938,10 +9938,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) { - int i, r; - unsigned long hva, old_npages; struct kvm_memslots *slots = kvm_memslots(kvm); struct kvm_memory_slot *slot; + unsigned long hva; + int i, r; lockdep_assert_held(&kvm->slots_lock); @@ -9965,8 +9965,7 @@ void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, if (!slot || !slot->npages) return NULL; - old_npages = slot->npages; - hva = slot->userspace_addr; + hva = 0; } for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) { @@ -9982,9 +9981,6 @@ void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, return ERR_PTR_USR(r); } - if (!size) - vm_munmap(hva, old_npages * PAGE_SIZE); - return (void __user *)hva; } EXPORT_SYMBOL_FOR_KVM_INTERNAL(__x86_set_memory_region); @@ -10013,20 +10009,6 @@ void kvm_arch_pre_destroy_vm(struct kvm *kvm) void kvm_arch_destroy_vm(struct kvm *kvm) { - if (current->mm == kvm->mm) { - /* - * Free memory regions allocated on behalf of userspace, - * unless the memory map has changed due to process exit - * or fd copying. - */ - mutex_lock(&kvm->slots_lock); - __x86_set_memory_region(kvm, APIC_ACCESS_PAGE_PRIVATE_MEMSLOT, - 0, 0); - __x86_set_memory_region(kvm, IDENTITY_PAGETABLE_PRIVATE_MEMSLOT, - 0, 0); - __x86_set_memory_region(kvm, TSS_PRIVATE_MEMSLOT, 0, 0); - mutex_unlock(&kvm->slots_lock); - } if (kvm->arch.created_mediated_pmu) perf_release_mediated_pmu(); kvm_destroy_vcpus(kvm); @@ -10066,6 +10048,16 @@ void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot) } kvm_page_track_free_memslot(slot); + + /* + * Free memory regions allocated on behalf of userspace, unless the + * memory map has changed due to process exit or fd copying. Leak the + * mapping on failure, e.g. if the task is killed, worst case scenario, + * the page(s) will be reclaimed when the process exits. + */ + if (current->mm == kvm->mm && slot->id >= KVM_USER_MEM_SLOTS && + !WARN_ON_ONCE(!slot->npages)) + vm_munmap(slot->userspace_addr, slot->npages * PAGE_SIZE); } int memslot_rmap_alloc(struct kvm_memory_slot *slot, unsigned long npages) -- 2.56.0.rc1.315.gc6ed9934b7-goog