From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97EFFC7618A for ; Mon, 20 Mar 2023 15:39:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233122AbjCTPjd (ORCPT ); Mon, 20 Mar 2023 11:39:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40726 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233206AbjCTPjM (ORCPT ); Mon, 20 Mar 2023 11:39:12 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2C51232E56 for ; Mon, 20 Mar 2023 08:30:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id BAEA1B80EC8 for ; Mon, 20 Mar 2023 15:30:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C47EC433EF; Mon, 20 Mar 2023 15:30:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1679326244; bh=4NgtUsg/Q2lOSKKQaoBTHaDt4aa3nA2cB2IgJwU3Z7k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SPuQosN7Zb56ZwXhDr986s+VzmiTjrZJT88a7kx4qTwUzjysPTgjMx45wHI0GgmDz nb4XNa9TyHMhn7uLji4Wbup+eqLiNjShri6W2v2dYR8CLks9rluSpFgFEXJqLMfYfX fi+cRuBd4PWKhQH5YpaEecjIw/YydI8o5BsAkFpA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Borislav Petkov (AMD)" , Tom Lendacky Subject: [PATCH 6.2 206/211] virt/coco/sev-guest: Simplify extended guest request handling Date: Mon, 20 Mar 2023 15:55:41 +0100 Message-Id: <20230320145522.162740531@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230320145513.305686421@linuxfoundation.org> References: <20230320145513.305686421@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Borislav Petkov (AMD) commit 970ab823743fb54b42002ec76c51481f67436444 upstream. Return a specific error code - -ENOSPC - to signal the too small cert data buffer instead of checking exit code and exitinfo2. While at it, hoist the *fw_err assignment in snp_issue_guest_request() so that a proper error value is returned to the callers. [ Tom: check override_err instead of err. ] Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Tom Lendacky Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230307192449.24732-4-bp@alien8.de Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/sev.c | 11 ++++--- drivers/virt/coco/sev-guest/sev-guest.c | 48 +++++++++++++++++--------------- 2 files changed, 32 insertions(+), 27 deletions(-) --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -2209,15 +2209,16 @@ int snp_issue_guest_request(u64 exit_cod if (ret) goto e_put; + *fw_err = ghcb->save.sw_exit_info_2; if (ghcb->save.sw_exit_info_2) { /* Number of expected pages are returned in RBX */ if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST && - ghcb->save.sw_exit_info_2 == SNP_GUEST_REQ_INVALID_LEN) + ghcb->save.sw_exit_info_2 == SNP_GUEST_REQ_INVALID_LEN) { input->data_npages = ghcb_get_rbx(ghcb); - - *fw_err = ghcb->save.sw_exit_info_2; - - ret = -EIO; + ret = -ENOSPC; + } else { + ret = -EIO; + } } e_put: --- a/drivers/virt/coco/sev-guest/sev-guest.c +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -322,7 +322,8 @@ static int handle_guest_request(struct s u8 type, void *req_buf, size_t req_sz, void *resp_buf, u32 resp_sz, __u64 *fw_err) { - unsigned long err; + unsigned long err, override_err = 0; + unsigned int override_npages = 0; u64 seqno; int rc; @@ -338,6 +339,7 @@ static int handle_guest_request(struct s if (rc) return rc; +retry_request: /* * Call firmware to process the request. In this function the encrypted * message enters shared memory with the host. So after this call the @@ -346,17 +348,24 @@ static int handle_guest_request(struct s */ rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err); - /* - * If the extended guest request fails due to having too small of a - * certificate data buffer, retry the same guest request without the - * extended data request in order to increment the sequence number - * and thus avoid IV reuse. - */ - if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST && - err == SNP_GUEST_REQ_INVALID_LEN) { - const unsigned int certs_npages = snp_dev->input.data_npages; + switch (rc) { + case -ENOSPC: + /* + * If the extended guest request fails due to having too + * small of a certificate data buffer, retry the same + * guest request without the extended data request in + * order to increment the sequence number and thus avoid + * IV reuse. + */ + override_npages = snp_dev->input.data_npages; + exit_code = SVM_VMGEXIT_GUEST_REQUEST; - exit_code = SVM_VMGEXIT_GUEST_REQUEST; + /* + * Override the error to inform callers the given extended + * request buffer size was too small and give the caller the + * required buffer size. + */ + override_err = SNP_GUEST_REQ_INVALID_LEN; /* * If this call to the firmware succeeds, the sequence number can @@ -366,15 +375,7 @@ static int handle_guest_request(struct s * of the VMPCK and the error code being propagated back to the * user as an ioctl() return code. */ - rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err); - - /* - * Override the error to inform callers the given extended - * request buffer size was too small and give the caller the - * required buffer size. - */ - err = SNP_GUEST_REQ_INVALID_LEN; - snp_dev->input.data_npages = certs_npages; + goto retry_request; } /* @@ -386,7 +387,10 @@ static int handle_guest_request(struct s snp_inc_msg_seqno(snp_dev); if (fw_err) - *fw_err = err; + *fw_err = override_err ?: err; + + if (override_npages) + snp_dev->input.data_npages = override_npages; /* * If an extended guest request was issued and the supplied certificate @@ -394,7 +398,7 @@ static int handle_guest_request(struct s * prevent IV reuse. If the standard request was successful, return -EIO * back to the caller as would have originally been returned. */ - if (!rc && err == SNP_GUEST_REQ_INVALID_LEN) + if (!rc && override_err == SNP_GUEST_REQ_INVALID_LEN) return -EIO; if (rc) {