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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81C9BC47080 for ; Wed, 2 Jun 2021 02:22:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 61F1061351 for ; Wed, 2 Jun 2021 02:22:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231164AbhFBCYK (ORCPT ); Tue, 1 Jun 2021 22:24:10 -0400 Received: from mga18.intel.com ([134.134.136.126]:39492 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230379AbhFBCXe (ORCPT ); Tue, 1 Jun 2021 22:23:34 -0400 IronPort-SDR: HNgGpPEJqLnMyf5xOHJqvhGU21StFtJn2x3RO+68TAHce1Gjxsp4PJyqW2mbGe7v3YQnsm9G1Z adpReFFSPH0g== X-IronPort-AV: E=McAfee;i="6200,9189,10002"; a="191037608" X-IronPort-AV: E=Sophos;i="5.83,241,1616482800"; d="scan'208";a="191037608" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2021 19:21:51 -0700 IronPort-SDR: A8txEX5/YF9jh1B/XH0xl7H5SqjgQhzhqcqPHPxXbqVaVroNYeqp23rC7PLosmOFRrpMJlA74g nJnVjNtMKTdA== X-IronPort-AV: E=Sophos;i="5.83,241,1616482800"; d="scan'208";a="633069246" Received: from mjdelaro-mobl.amr.corp.intel.com (HELO skuppusw-desk1.amr.corp.intel.com) ([10.254.3.23]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jun 2021 19:21:51 -0700 From: Kuppuswamy Sathyanarayanan To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Peter Zijlstra , Andy Lutomirski Cc: Peter H Anvin , Dave Hansen , Tony Luck , Dan Williams , Andi Kleen , Kirill Shutemov , Kuppuswamy Sathyanarayanan , Sean Christopherson , Kuppuswamy Sathyanarayanan , linux-kernel@vger.kernel.org, x86@kernel.org Subject: [PATCH v1 10/11] x86/tdx: Add MSR support for TDX guest Date: Tue, 1 Jun 2021 19:21:35 -0700 Message-Id: <20210602022136.2186759-11-sathyanarayanan.kuppuswamy@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210602022136.2186759-1-sathyanarayanan.kuppuswamy@linux.intel.com> References: <20210602022136.2186759-1-sathyanarayanan.kuppuswamy@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Kirill A. Shutemov" Operations on context-switched MSRs can be run natively. The rest of MSRs should be handled through TDVMCALLs. TDVMCALL[Instruction.RDMSR] and TDVMCALL[Instruction.WRMSR] provide MSR oprations. You can find RDMSR and WRMSR details in Guest-Host-Communication Interface (GHCI) for Intel Trust Domain Extensions (Intel TDX) specification, sec 3.10, 3.11. Signed-off-by: Kirill A. Shutemov Reviewed-by: Andi Kleen Reviewed-by: Tony Luck Signed-off-by: Kuppuswamy Sathyanarayanan --- arch/x86/kernel/tdx.c | 67 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 65 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c index 76b71bf56b81..af7acea500ab 100644 --- a/arch/x86/kernel/tdx.c +++ b/arch/x86/kernel/tdx.c @@ -115,6 +115,55 @@ static __cpuidle void tdg_safe_halt(void) BUG_ON(ret); } +static bool tdg_is_context_switched_msr(unsigned int msr) +{ + switch (msr) { + case MSR_EFER: + case MSR_IA32_CR_PAT: + case MSR_FS_BASE: + case MSR_GS_BASE: + case MSR_KERNEL_GS_BASE: + case MSR_IA32_SYSENTER_CS: + case MSR_IA32_SYSENTER_EIP: + case MSR_IA32_SYSENTER_ESP: + case MSR_STAR: + case MSR_LSTAR: + case MSR_SYSCALL_MASK: + case MSR_IA32_XSS: + case MSR_TSC_AUX: + case MSR_IA32_BNDCFGS: + return true; + } + return false; +} + +static u64 tdg_read_msr_safe(unsigned int msr, int *err) +{ + u64 ret; + struct tdx_hypercall_output out = {0}; + + WARN_ON_ONCE(tdg_is_context_switched_msr(msr)); + + ret = __tdx_hypercall(EXIT_REASON_MSR_READ, msr, 0, 0, 0, &out); + + *err = ret ? -EIO : 0; + + return out.r11; +} + +static int tdg_write_msr_safe(unsigned int msr, unsigned int low, + unsigned int high) +{ + u64 ret; + + WARN_ON_ONCE(tdg_is_context_switched_msr(msr)); + + ret = __tdx_hypercall(EXIT_REASON_MSR_WRITE, msr, (u64)high << 32 | low, + 0, 0, NULL); + + return ret ? -EIO : 0; +} + unsigned long tdg_get_ve_info(struct ve_info *ve) { u64 ret; @@ -141,19 +190,33 @@ unsigned long tdg_get_ve_info(struct ve_info *ve) int tdg_handle_virtualization_exception(struct pt_regs *regs, struct ve_info *ve) { + unsigned long val; + int ret = 0; + switch (ve->exit_reason) { case EXIT_REASON_HLT: tdg_halt(); break; + case EXIT_REASON_MSR_READ: + val = tdg_read_msr_safe(regs->cx, (unsigned int *)&ret); + if (!ret) { + regs->ax = val & UINT_MAX; + regs->dx = val >> 32; + } + break; + case EXIT_REASON_MSR_WRITE: + ret = tdg_write_msr_safe(regs->cx, regs->ax, regs->dx); + break; default: pr_warn("Unexpected #VE: %lld\n", ve->exit_reason); return -EFAULT; } /* After successful #VE handling, move the IP */ - regs->ip += ve->instr_len; + if (!ret) + regs->ip += ve->instr_len; - return 0; + return ret; } void __init tdx_early_init(void) -- 2.25.1