From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) (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 906F949CF34 for ; Thu, 1 Oct 2026 20:22:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790886174; cv=none; b=QVXtuSYyivQLXCXpefk+4ucVMcBIm5oEaWnWfjanrNm1Mfw8qH/MQocWwE1UbEmM/h8TysHf4oNI/MsIellvL5Tw8MMshlilSdTgV1HrtqYtD5rEfkPyPb0b28PHCZMI673jBSyjqoLSMeyN6G89sH+CCIQGIHIbGq6+6G4WL9c= 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=lYZFA25P; arc=none smtp.client-ip=209.85.210.200 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="lYZFA25P" Received: by mail-pf1-f200.google.com with SMTP id d2e1a72fcca58-88078ca8725so2502119b3a.1 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=1790886166; x=1791490966; 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=lYZFA25PuQHWc1asBBH0KvT+kJTFYu857r5N7rVCAs+nGLK+zghmW2PTubPbC43r/e Fvtk9Vs2OngTtwtkr/tVDDNHZ5KdsCHPhqOE3EeIY+m9gXz+9nIZMG8RZdErs2eZYOD2 oGWzyFnfdUtqs5kWNrvwV45fNWTXYzh9GJRLEM03xyQrolA0VEePfQDXcmJ3YXSBFQKx 39ubhsudnrwOX1CidV5a4V3dRyC2MyrXBhZ7wXtWPSEAzMfTJ6d/Q831Y/0ELpRiPW2Y FzWVKEy3zjzlNkhkJPxngLdru/mzWz0HvKaEsV1vf65y1uNIgjNcOpsFjtYnnngtrJ92 wBug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790886166; x=1791490966; 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=OdlBMbF7gJ7C5XiROHW4K5WKzS65dvW1+N/18uYByWynmR6hZwtf9pkWm4c44uV4e7 CnMAhIzMdUw7Q/d6xQ6WZzqny1yEAIIJFFnRbfm2tBX+SAeXk+UXBLCIcM/uuFoX5S1c AOLlVAZqWkb6ZRI7FyNrLAR2az8LPR1bfxEZJHhKNgDiZubmMQ+7RtzwoEV8VYDwt6P1 BSGubhLeEgEGBn3bF12j3JDxiiN/9ibxZCDSmgdtv4kxCsJnOr7lg2rEwURcEtEEdZdJ YaRgph4JE3sya1LZSWJN1P83IgV3NC7eU4S4y/ybK2HR0HTrWL6QeSqUxtofTnMb/B7L 4wIw== X-Forwarded-Encrypted: i=1; AKwUvBwGqhodQW9Zdc+53qHyWoCThSfgNqzn9BCnm2tGPth+/o4ZEg6TUtU/etkPudBpz9S4IWeBWALnOgngOwo=@vger.kernel.org X-Gm-Message-State: AFuF++nV9gOISJrIdkjZqSONh82D8O+xW0tknUZSNZaANDZj0spvUten uiuWxwZNDnij2R86RyvJuxR6XhhyaaUdMOA1PQRV6skgu6xEMMvX3d8hD29bYC/WJs0kwfzm55z W9XEFyQ== 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: linux-kernel@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