From patchwork Wed May 12 14:42:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 438381 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, 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 BD547C43140 for ; Wed, 12 May 2021 15:59:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8170061CC2 for ; Wed, 12 May 2021 15:59:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231363AbhELQAh (ORCPT ); Wed, 12 May 2021 12:00:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:37076 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237754AbhELP4T (ORCPT ); Wed, 12 May 2021 11:56:19 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id DE85E61927; Wed, 12 May 2021 15:28:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620833311; bh=h59MSIG9erklP9in9YiIPm0y8p9QmQYL0ytDECAvG+0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M9Vj+CXGqQJtHV3BMVrf0vROUHM/IiGhEdqNfWeDkVvmhURJop8KHHA6al/wxtX0E 15UBpXManVVwTPUrpQbJXRnlW0aWSS4BJkWTfu5hMNHVuABv9hxQBQzISJCZPa+B0H VfcmgGU4rlOr28ntI/t34DtVwLSCU8fsIws8enw8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Babu Moger , Sean Christopherson , Paolo Bonzini Subject: [PATCH 5.11 098/601] KVM: x86: Remove emulators broken checks on CR0/CR3/CR4 loads Date: Wed, 12 May 2021 16:42:55 +0200 Message-Id: <20210512144831.053626965@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210512144827.811958675@linuxfoundation.org> References: <20210512144827.811958675@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sean Christopherson commit d0fe7b6404408835ed60232cb3bf28324b2f95db upstream. Remove the emulator's checks for illegal CR0, CR3, and CR4 values, as the checks are redundant, outdated, and in the case of SEV's C-bit, broken. The emulator manually calculates MAXPHYADDR from CPUID and neglects to mask off the C-bit. For all other checks, kvm_set_cr*() are a superset of the emulator checks, e.g. see CR4.LA57. Fixes: a780a3ea6282 ("KVM: X86: Fix reserved bits check for MOV to CR3") Cc: Babu Moger Signed-off-by: Sean Christopherson Message-Id: <20210422022128.3464144-2-seanjc@google.com> Cc: stable@vger.kernel.org [Unify check_cr_read and check_cr_write. - Paolo] Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/emulate.c | 80 +------------------------------------------------ 1 file changed, 3 insertions(+), 77 deletions(-) --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -4220,7 +4220,7 @@ static bool valid_cr(int nr) } } -static int check_cr_read(struct x86_emulate_ctxt *ctxt) +static int check_cr_access(struct x86_emulate_ctxt *ctxt) { if (!valid_cr(ctxt->modrm_reg)) return emulate_ud(ctxt); @@ -4228,80 +4228,6 @@ static int check_cr_read(struct x86_emul return X86EMUL_CONTINUE; } -static int check_cr_write(struct x86_emulate_ctxt *ctxt) -{ - u64 new_val = ctxt->src.val64; - int cr = ctxt->modrm_reg; - u64 efer = 0; - - static u64 cr_reserved_bits[] = { - 0xffffffff00000000ULL, - 0, 0, 0, /* CR3 checked later */ - CR4_RESERVED_BITS, - 0, 0, 0, - CR8_RESERVED_BITS, - }; - - if (!valid_cr(cr)) - return emulate_ud(ctxt); - - if (new_val & cr_reserved_bits[cr]) - return emulate_gp(ctxt, 0); - - switch (cr) { - case 0: { - u64 cr4; - if (((new_val & X86_CR0_PG) && !(new_val & X86_CR0_PE)) || - ((new_val & X86_CR0_NW) && !(new_val & X86_CR0_CD))) - return emulate_gp(ctxt, 0); - - cr4 = ctxt->ops->get_cr(ctxt, 4); - ctxt->ops->get_msr(ctxt, MSR_EFER, &efer); - - if ((new_val & X86_CR0_PG) && (efer & EFER_LME) && - !(cr4 & X86_CR4_PAE)) - return emulate_gp(ctxt, 0); - - break; - } - case 3: { - u64 rsvd = 0; - - ctxt->ops->get_msr(ctxt, MSR_EFER, &efer); - if (efer & EFER_LMA) { - u64 maxphyaddr; - u32 eax, ebx, ecx, edx; - - eax = 0x80000008; - ecx = 0; - if (ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, - &edx, true)) - maxphyaddr = eax & 0xff; - else - maxphyaddr = 36; - rsvd = rsvd_bits(maxphyaddr, 63); - if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_PCIDE) - rsvd &= ~X86_CR3_PCID_NOFLUSH; - } - - if (new_val & rsvd) - return emulate_gp(ctxt, 0); - - break; - } - case 4: { - ctxt->ops->get_msr(ctxt, MSR_EFER, &efer); - - if ((efer & EFER_LMA) && !(new_val & X86_CR4_PAE)) - return emulate_gp(ctxt, 0); - - break; - } - } - - return X86EMUL_CONTINUE; -} - static int check_dr7_gd(struct x86_emulate_ctxt *ctxt) { unsigned long dr7; @@ -4841,10 +4767,10 @@ static const struct opcode twobyte_table D(ImplicitOps | ModRM | SrcMem | NoAccess), /* 8 * reserved NOP */ D(ImplicitOps | ModRM | SrcMem | NoAccess), /* NOP + 7 * reserved NOP */ /* 0x20 - 0x2F */ - DIP(ModRM | DstMem | Priv | Op3264 | NoMod, cr_read, check_cr_read), + DIP(ModRM | DstMem | Priv | Op3264 | NoMod, cr_read, check_cr_access), DIP(ModRM | DstMem | Priv | Op3264 | NoMod, dr_read, check_dr_read), IIP(ModRM | SrcMem | Priv | Op3264 | NoMod, em_cr_write, cr_write, - check_cr_write), + check_cr_access), IIP(ModRM | SrcMem | Priv | Op3264 | NoMod, em_dr_write, dr_write, check_dr_write), N, N, N, N,