From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (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 C01C9367B66 for ; Fri, 22 May 2026 17:21:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779470517; cv=none; b=A8gNAnGXPM4nGnJIXn4LBEgdArdh+ou2J8Pw6O/3kfIY1juhpc/r5NH8QobdP6oo8wxH3CsRVMoySt67TTI2korzL+ViKf6z3IwRhsMDfnQqFMMCbNLRrTBpP1Gzyjx22JOeK+FbdLQUGOUk3o1pmYY5yQUVq23fzraOkuTh7FI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779470517; c=relaxed/simple; bh=ayQtNuu0KAGI/GVpUUq/PzEm+KPC5bq0/iohzWO2RXQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=jY7u2jm7jGfJQ6kczfOIpeAUtO7EH0Vs80M3tL2nlgenrsITnHMU/1p9v9B2zePkmX3BrLq7rNtUvHBx7pmuxOW9VLghLfCg3CbZFDS4EcOIpyMyv0WRKPViO2dmsqHoPMTvhXN8YxPIe2g4ieNlZRihTurzkttQqBldE1YQlYs= 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=UVSufxdN; arc=none smtp.client-ip=209.85.210.201 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="UVSufxdN" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-83f24cd00f8so4065567b3a.0 for ; Fri, 22 May 2026 10:21:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1779470515; x=1780075315; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=yzw6ZBZmJ6GLsKKeZffOS4D7Mu6oc4MX0x50fzU1G54=; b=UVSufxdN6A8mHOcpDPxbQOi3K0fT1Q/SQu8erU7w8b0rZIWbx6tjGMPE53cpDXvjOw ovznUYEx/iXb6N4n5heqnJ2Xa4Y1fnVFA1t4kxY9kK6mDDNUxxWYpWZtczEnbusjKlNF r88FY8evtBzCOBt1vHA1MFXVL381kSVlq7NPqS3RQUldRTq+NftWaZIfJrOuBDwAQWfN fiWWiIQOvvAEoRHuHVnB+kqTHEUJ7Zu7EGPR+G/LdEQh9zadQjfMsBf7HAOtfHA5O0vG yhIHh2/e5VgDzL/tEu1XLB+GEmVutFA+Nn1iQfBTJYEkNyDqOzr2+N592qp+e+qd7f4V oBhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779470515; x=1780075315; h=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; bh=yzw6ZBZmJ6GLsKKeZffOS4D7Mu6oc4MX0x50fzU1G54=; b=aa3xzIYgw0NYT29MfpMTbazaF6QfmpJzBKyPaZxAAfe5aA/pUMxf7AKceL0dA/OAmx INsJXfRdxyrWUSv2Y/XhJtsRpjXep+pVMZvtsfh9KkoYrnFIe2h+iU7oq754jjw9g7Rm U8DikQUQgtajAnF5g05duPMOa1NUA3LGup78rqvusv5UmrHMgmX6t74a8L7kYX25Xba6 Uey1xpCAGmgaaQsh216L0cZk3FCGADxwX/v+3o13WIe8kPWHVkMRpXQmbkZZ0rK6KIe+ q596x+ThlK/5UwGmAFCm28AoDbOxNtLf3BsomL5MuluIPyO/8BmG3u9OslJ1YGnSe7De bNjg== X-Forwarded-Encrypted: i=1; AFNElJ9h/jih5UT/rAQH07gAIWNsJIgwzVfs6QzMciB7NVuT9NeUXcFYKrrmmKqgiy4zoeVH3W7PJ2OgutDkR3Y=@vger.kernel.org X-Gm-Message-State: AOJu0YxBz1vstLSjT9+ebKX1zWilu4zDauSHUmJiyJxSxMhk4uZcfmtr E+felXt4guT6xroueq8S2qQ5tO/CJIP2bWp65foHaclUBvI0eip2fCpj7tzSJz3hJs4nFSh+Esb 35x5faw== X-Received: from pfbkt5.prod.google.com ([2002:a05:6a00:4ba5:b0:82f:9be8:3f2c]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:1ca8:b0:837:6bb9:acd5 with SMTP id d2e1a72fcca58-8415ef52165mr4423320b3a.0.1779470514560; Fri, 22 May 2026 10:21:54 -0700 (PDT) Reply-To: Sean Christopherson Date: Fri, 22 May 2026 10:21:49 -0700 In-Reply-To: <20260522172151.3530267-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260522172151.3530267-1-seanjc@google.com> X-Mailer: git-send-email 2.54.0.794.g4f17f83d09-goog Message-ID: <20260522172151.3530267-2-seanjc@google.com> Subject: [PATCH v2 1/3] KVM: guest_memfd: Return -EEXIST for overlapping bindings From: Sean Christopherson To: Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Zongyao Chen , Ackerley Tng , Sean Christopherson Content-Type: text/plain; charset="UTF-8" From: Zongyao Chen KVM_SET_USER_MEMORY_REGION2 rejects guest_memfd ranges that overlap an existing binding, but kvm_gmem_bind() currently reports the failure through its generic -EINVAL path. That makes binding conflicts indistinguishable from malformed guest_memfd parameters. Return -EEXIST when the target guest_memfd range is already bound, matching the errno used for overlapping GPA memslots and making the two types of range conflicts report the same class of error to userspace. Note, returning -EINVAL was definitely not intentional, as guest_memfd support was accompanied by a selftest to verify that attempting to create overlapping bindings fails with -EEXIST. Except the selftest was also flawed in that it unintentionally overlapped memslot GPAs, and so failed on KVM's common memslot checks before reaching guest_memfd. Fixes: a7800aa80ea4 ("KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory") Signed-off-by: Zongyao Chen Reviewed-by: Ackerley Tng Tested-by: Ackerley Tng [sean: call out that the original intent was to return -EEXIST] Signed-off-by: Sean Christopherson --- virt/kvm/guest_memfd.c | 1 + 1 file changed, 1 insertion(+) diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 69c9d6d546b2..46727539d08a 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -675,6 +675,7 @@ int kvm_gmem_bind(struct kvm *kvm, struct kvm_memory_slot *slot, if (!xa_empty(&f->bindings) && xa_find(&f->bindings, &start, end - 1, XA_PRESENT)) { + r = -EEXIST; filemap_invalidate_unlock(inode->i_mapping); goto err; } -- 2.54.0.794.g4f17f83d09-goog