From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DA113195FEC; Mon, 21 Oct 2024 10:36:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729506993; cv=none; b=YboKQQQbmM0rfvLbzS+l+QZC9eDF88tyYzyyd/7j2byUbS3QlN9Rp3JGcCy7QRJfHUFwu4RNQ5KKtsas8ijeGpyhqjloYheCR9Q58FIIqMTpz0HHXzxrWrEHSPYyB/TfPmP5qeGykg4DyJw2KoW3XqEOjTKfcyjEqiRP0qFglGQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729506993; c=relaxed/simple; bh=Y4iE72LHV9l6YQR/BPzs0UX6mTkWbbHYwbDU3NcRIjg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LBbvXLSmHwpXVVUu0XEaCJd8AdCxB2K/LyLan69prFUoDXoFub5IliL23KbwHeUdrz98PBOhhVs0SOhyukbQCshST74OaLAQ5thabmYGEx+Q7PzYjK9fRDFjuAvSuG1p2jsVRZ56F16fvRU8HFr1w20PDeyOITjWAcfnSueQBSc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hESZ+PTN; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hESZ+PTN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 14E29C4CEC7; Mon, 21 Oct 2024 10:36:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1729506992; bh=Y4iE72LHV9l6YQR/BPzs0UX6mTkWbbHYwbDU3NcRIjg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hESZ+PTN/WxKS6kdLA3XUwcU7AtNx6JlLt9TYP/jURejnA++1qB4HhFnreHqWUR0L QacEY8mv0utw1q/BNEIfmbzYzI27cKlflmGkyEY4CKsQoE1rtdrSYABoeo8H2kiqVt T5mE2dlSRpeP5/MmPAmvEc6MIROeF/eed9fspn8E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Nico Boehr , Heiko Carstens , Janosch Frank Subject: [PATCH 6.6 052/124] KVM: s390: gaccess: Check if guest address is in memslot Date: Mon, 21 Oct 2024 12:24:16 +0200 Message-ID: <20241021102258.743453118@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241021102256.706334758@linuxfoundation.org> References: <20241021102256.706334758@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nico Boehr commit e8061f06185be0a06a73760d6526b8b0feadfe52 upstream. Previously, access_guest_page() did not check whether the given guest address is inside of a memslot. This is not a problem, since kvm_write_guest_page/kvm_read_guest_page return -EFAULT in this case. However, -EFAULT is also returned when copy_to/from_user fails. When emulating a guest instruction, the address being outside a memslot usually means that an addressing exception should be injected into the guest. Failure in copy_to/from_user however indicates that something is wrong in userspace and hence should be handled there. To be able to distinguish these two cases, return PGM_ADDRESSING in access_guest_page() when the guest address is outside guest memory. In access_guest_real(), populate vcpu->arch.pgm.code such that kvm_s390_inject_prog_cond() can be used in the caller for injecting into the guest (if applicable). Since this adds a new return value to access_guest_page(), we need to make sure that other callers are not confused by the new positive return value. There are the following users of access_guest_page(): - access_guest_with_key() does the checking itself (in guest_range_to_gpas()), so this case should never happen. Even if, the handling is set up properly. - access_guest_real() just passes the return code to its callers, which are: - read_guest_real() - see below - write_guest_real() - see below There are the following users of read_guest_real(): - ar_translation() in gaccess.c which already returns PGM_* - setup_apcb10(), setup_apcb00(), setup_apcb11() in vsie.c which always return -EFAULT on read_guest_read() nonzero return - no change - shadow_crycb(), handle_stfle() always present this as validity, this could be handled better but doesn't change current behaviour - no change There are the following users of write_guest_real(): - kvm_s390_store_status_unloaded() always returns -EFAULT on write_guest_real() failure. Fixes: 2293897805c2 ("KVM: s390: add architecture compliant guest access functions") Cc: stable@vger.kernel.org Signed-off-by: Nico Boehr Reviewed-by: Heiko Carstens Link: https://lore.kernel.org/r/20240917151904.74314-2-nrb@linux.ibm.com Acked-by: Janosch Frank Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman --- arch/s390/kvm/gaccess.c | 4 ++++ arch/s390/kvm/gaccess.h | 14 ++++++++------ 2 files changed, 12 insertions(+), 6 deletions(-) --- a/arch/s390/kvm/gaccess.c +++ b/arch/s390/kvm/gaccess.c @@ -1001,6 +1001,8 @@ static int access_guest_page(struct kvm const gfn_t gfn = gpa_to_gfn(gpa); int rc; + if (!gfn_to_memslot(kvm, gfn)) + return PGM_ADDRESSING; if (mode == GACC_STORE) rc = kvm_write_guest_page(kvm, gfn, data, offset, len); else @@ -1158,6 +1160,8 @@ int access_guest_real(struct kvm_vcpu *v gra += fragment_len; data += fragment_len; } + if (rc > 0) + vcpu->arch.pgm.code = rc; return rc; } --- a/arch/s390/kvm/gaccess.h +++ b/arch/s390/kvm/gaccess.h @@ -405,11 +405,12 @@ int read_guest_abs(struct kvm_vcpu *vcpu * @len: number of bytes to copy * * Copy @len bytes from @data (kernel space) to @gra (guest real address). - * It is up to the caller to ensure that the entire guest memory range is - * valid memory before calling this function. * Guest low address and key protection are not checked. * - * Returns zero on success or -EFAULT on error. + * Returns zero on success, -EFAULT when copying from @data failed, or + * PGM_ADRESSING in case @gra is outside a memslot. In this case, pgm check info + * is also stored to allow injecting into the guest (if applicable) using + * kvm_s390_inject_prog_cond(). * * If an error occurs data may have been copied partially to guest memory. */ @@ -428,11 +429,12 @@ int write_guest_real(struct kvm_vcpu *vc * @len: number of bytes to copy * * Copy @len bytes from @gra (guest real address) to @data (kernel space). - * It is up to the caller to ensure that the entire guest memory range is - * valid memory before calling this function. * Guest key protection is not checked. * - * Returns zero on success or -EFAULT on error. + * Returns zero on success, -EFAULT when copying to @data failed, or + * PGM_ADRESSING in case @gra is outside a memslot. In this case, pgm check info + * is also stored to allow injecting into the guest (if applicable) using + * kvm_s390_inject_prog_cond(). * * If an error occurs data may have been copied partially to kernel space. */