From patchwork Thu Mar 19 09:13:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joerg Roedel X-Patchwork-Id: 11446823 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EAED31874 for ; Thu, 19 Mar 2020 09:17:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D36E820770 for ; Thu, 19 Mar 2020 09:17:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727386AbgCSJRl (ORCPT ); Thu, 19 Mar 2020 05:17:41 -0400 Received: from 8bytes.org ([81.169.241.247]:52340 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727372AbgCSJOh (ORCPT ); Thu, 19 Mar 2020 05:14:37 -0400 Received: by theia.8bytes.org (Postfix, from userid 1000) id 726327AB; Thu, 19 Mar 2020 10:14:23 +0100 (CET) From: Joerg Roedel To: x86@kernel.org Cc: hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Thomas Hellstrom , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, Joerg Roedel , Joerg Roedel Subject: [PATCH 38/70] x86/sev-es: Setup early #VC handler Date: Thu, 19 Mar 2020 10:13:35 +0100 Message-Id: <20200319091407.1481-39-joro@8bytes.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200319091407.1481-1-joro@8bytes.org> References: <20200319091407.1481-1-joro@8bytes.org> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Joerg Roedel Setup an early handler for #VC exceptions. There is no GHCB mapped yet, so just re-use the vc_no_ghcb_handler. It can only handle CPUID exit-codes, but that should be enough to get the kernel through verify_cpu() and __startup_64() until it runs on virtual addresses. Signed-off-by: Joerg Roedel --- arch/x86/include/asm/desc.h | 1 + arch/x86/include/asm/processor.h | 1 + arch/x86/include/asm/sev-es.h | 2 ++ arch/x86/kernel/head64.c | 17 +++++++++++++++ arch/x86/kernel/head_64.S | 36 ++++++++++++++++++++++++++++++++ arch/x86/kernel/idt.c | 10 +++++++++ 6 files changed, 67 insertions(+) diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h index 80bf63c08007..30e2a0e863b6 100644 --- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -388,6 +388,7 @@ static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit) void update_intr_gate(unsigned int n, const void *addr); void alloc_intr_gate(unsigned int n, const void *addr); +void set_early_idt_handler(gate_desc *idt, int n, void *handler); static inline void init_idt_data(struct idt_data *data, unsigned int n, const void *addr) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 09705ccc393c..4622427d01d4 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -768,6 +768,7 @@ extern int sysenter_setup(void); /* Defined in head.S */ extern struct desc_ptr early_gdt_descr; +extern struct desc_ptr early_idt_descr; extern void switch_to_new_gdt(int); extern void load_direct_gdt(int); diff --git a/arch/x86/include/asm/sev-es.h b/arch/x86/include/asm/sev-es.h index 512d3ccb9832..caa29f75ce41 100644 --- a/arch/x86/include/asm/sev-es.h +++ b/arch/x86/include/asm/sev-es.h @@ -75,4 +75,6 @@ static inline u64 copy_lower_bits(u64 out, u64 in, unsigned int bits) return out; } +extern void early_vc_handler(void); + #endif diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 8ccca109750d..b8613fc0a364 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -38,6 +38,7 @@ #include #include #include +#include /* * Manage page tables very early on. @@ -515,3 +516,19 @@ void __head early_idt_setup_early_handler(unsigned long physaddr) native_write_idt_entry(idt, i, &desc); } } + +void __head early_idt_setup(unsigned long physbase) +{ + gate_desc *idt = fixup_pointer(idt_table, physbase); + void __maybe_unused *handler; + +#ifdef CONFIG_AMD_MEM_ENCRYPT + /* VMM Communication Exception */ + handler = fixup_pointer(early_vc_handler, physbase); + set_early_idt_handler(idt, X86_TRAP_VC, handler); +#endif + + /* Initialize IDT descriptor and load IDT */ + early_idt_descr.address = (unsigned long)idt; + native_load_idt(&early_idt_descr); +} diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index bc0622a72d6d..b3acecdabd34 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -92,6 +92,12 @@ SYM_CODE_START_NOALIGN(startup_64) .Lon_kernel_cs: UNWIND_HINT_EMPTY + /* Setup IDT - Needed for SEV-ES */ + leaq _text(%rip), %rdi + pushq %rsi + call early_idt_setup + popq %rsi + /* Sanitize CPU configuration */ call verify_cpu @@ -370,6 +376,33 @@ SYM_CODE_START_LOCAL(early_idt_handler_common) jmp restore_regs_and_return_to_kernel SYM_CODE_END(early_idt_handler_common) +#ifdef CONFIG_AMD_MEM_ENCRYPT +/* + * VC Exception handler used during very early boot. The + * early_idt_handler_array can't be used because it returns via the + * paravirtualized INTERRUPT_RETURN and pv-ops don't work that early. + */ +SYM_CODE_START_NOALIGN(early_vc_handler) + UNWIND_HINT_IRET_REGS offset=8 + + /* Build pt_regs */ + PUSH_AND_CLEAR_REGS + + /* Call C handler */ + movq %rsp, %rdi + movq ORIG_RAX(%rsp), %rsi + call vc_no_ghcb_handler + + /* Unwind pt_regs */ + POP_REGS + + /* Remove Error Code */ + addq $8, %rsp + + /* Pure iret required here - don't use INTERRUPT_RETURN */ + iretq +SYM_CODE_END(early_vc_handler) +#endif #define SYM_DATA_START_PAGE_ALIGNED(name) \ SYM_START(name, SYM_L_GLOBAL, .balign PAGE_SIZE) @@ -511,6 +544,9 @@ SYM_DATA_END(level1_fixmap_pgt) SYM_DATA(early_gdt_descr, .word GDT_ENTRIES*8-1) SYM_DATA_LOCAL(early_gdt_descr_base, .quad INIT_PER_CPU_VAR(gdt_page)) +SYM_DATA(early_idt_descr, .word NUM_EXCEPTION_VECTORS * 16) +SYM_DATA_LOCAL(early_idt_descr_base, .quad 0) + .align 16 /* This must match the first entry in level2_kernel_pgt */ SYM_DATA(phys_base, .quad 0x0) diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c index 4a2c7791c697..135d208a2d38 100644 --- a/arch/x86/kernel/idt.c +++ b/arch/x86/kernel/idt.c @@ -341,3 +341,13 @@ void alloc_intr_gate(unsigned int n, const void *addr) if (!test_and_set_bit(n, system_vectors)) set_intr_gate(n, addr); } + +void set_early_idt_handler(gate_desc *idt, int n, void *handler) +{ + struct idt_data data; + gate_desc desc; + + init_idt_data(&data, n, handler); + idt_init_desc(&desc, &data); + native_write_idt_entry(idt, n, &desc); +}