From: Joerg Roedel <joro@8bytes.org>
To: x86@kernel.org
Cc: Joerg Roedel <joro@8bytes.org>, Joerg Roedel <jroedel@suse.de>,
hpa@zytor.com, Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Jiri Slaby <jslaby@suse.cz>,
Dan Williams <dan.j.williams@intel.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Juergen Gross <jgross@suse.com>,
Kees Cook <keescook@chromium.org>,
David Rientjes <rientjes@google.com>,
Cfir Cohen <cfir@google.com>, Erdem Aktas <erdemaktas@google.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mike Stunes <mstunes@vmware.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Martin Radev <martin.b.radev@gmail.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org
Subject: [PATCH 3/7] x86/boot/compressed/64: Setup IDT in startup_32 boot path
Date: Wed, 10 Feb 2021 11:21:31 +0100 [thread overview]
Message-ID: <20210210102135.30667-4-joro@8bytes.org> (raw)
In-Reply-To: <20210210102135.30667-1-joro@8bytes.org>
From: Joerg Roedel <jroedel@suse.de>
This boot path needs exception handling when it is used with SEV-ES.
Setup an IDT and provide a helper function to write IDT entries for
use in 32-bit protected mode.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
arch/x86/boot/compressed/head_64.S | 73 +++++++++++++++++++++++++++++-
1 file changed, 72 insertions(+), 1 deletion(-)
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index c59c80ca546d..8deeec78cdb4 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -116,6 +116,11 @@ SYM_FUNC_START(startup_32)
lretl
1:
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+ /* Setup Exception handling for SEV-ES */
+ call startup32_load_idt
+#endif
+
/* Make sure cpu supports long mode. */
call verify_cpu
testl %eax, %eax
@@ -528,7 +533,6 @@ SYM_FUNC_END_ALIAS(efi_stub_entry)
.text
SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated)
-
/*
* Clear BSS (stack is currently empty)
*/
@@ -701,6 +705,19 @@ SYM_DATA_START(boot_idt)
.endr
SYM_DATA_END_LABEL(boot_idt, SYM_L_GLOBAL, boot_idt_end)
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+SYM_DATA_START(boot32_idt_desc)
+ .word boot32_idt_end - boot32_idt - 1
+ .long 0
+SYM_DATA_END(boot32_idt_desc)
+ .balign 8
+SYM_DATA_START(boot32_idt)
+ .rept 32
+ .quad 0
+ .endr
+SYM_DATA_END_LABEL(boot32_idt, SYM_L_GLOBAL, boot32_idt_end)
+#endif
+
#ifdef CONFIG_EFI_STUB
SYM_DATA(image_offset, .long 0)
#endif
@@ -793,6 +810,60 @@ SYM_DATA_START_LOCAL(loaded_image_proto)
SYM_DATA_END(loaded_image_proto)
#endif
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+ __HEAD
+ .code32
+/*
+ * Write an IDT entry into boot32_idt
+ *
+ * Parameters:
+ *
+ * %eax: Handler address
+ * %edx: Vector number
+ *
+ * Physical offset is expected in %ebp
+ */
+SYM_FUNC_START(startup32_set_idt_entry)
+ push %ebx
+ push %ecx
+
+ /* IDT entry address to %ebx */
+ leal rva(boot32_idt)(%ebp), %ebx
+ shl $3, %edx
+ addl %edx, %ebx
+
+ /* Build IDT entry, lower 4 bytes */
+ movl %eax, %edx
+ andl $0x0000ffff, %edx
+ movl $__KERNEL32_CS, %ecx
+ shl $16, %ecx
+ orl %ecx, %edx
+
+ /* Store lower 4 bytes to IDT */
+ movl %edx, (%ebx)
+
+ /* Build IDT entry, upper 4 bytes */
+ movl %eax, %edx
+ andl $0xffff0000, %edx
+ orl $0x00008e00, %edx
+
+ /* Store upper 4 bytes to IDT */
+ movl %edx, 4(%ebx)
+
+ pop %ecx
+ pop %ebx
+ ret
+SYM_FUNC_END(startup32_set_idt_entry)
+
+SYM_FUNC_START(startup32_load_idt)
+ /* Load IDT */
+ leal rva(boot32_idt)(%ebp), %eax
+ movl %eax, rva(boot32_idt_desc+2)(%ebp)
+ lidt rva(boot32_idt_desc)(%ebp)
+
+ ret
+SYM_FUNC_END(startup32_load_idt)
+#endif
/*
* Stack and heap for uncompression
*/
--
2.30.0
next prev parent reply other threads:[~2021-02-10 10:32 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-10 10:21 [PATCH 0/7] x86/seves: Support 32-bit boot path and other updates Joerg Roedel
2021-02-10 10:21 ` [PATCH 1/7] x86/boot/compressed/64: Cleanup exception handling before booting kernel Joerg Roedel
2021-02-10 10:21 ` [PATCH 2/7] x86/boot/compressed/64: Reload CS in startup_32 Joerg Roedel
2021-02-10 10:21 ` Joerg Roedel [this message]
2021-02-24 10:49 ` [PATCH 3/7] x86/boot/compressed/64: Setup IDT in startup_32 boot path Borislav Petkov
2021-02-10 10:21 ` [PATCH 4/7] x86/boot/compressed/64: Add 32-bit boot #VC handler Joerg Roedel
2021-02-25 12:13 ` Borislav Petkov
2021-02-10 10:21 ` [PATCH 5/7] x86/boot/compressed/64: Add CPUID sanity check to 32-bit boot-path Joerg Roedel
2021-02-10 10:21 ` [PATCH 6/7] x86/boot/compressed/64: Check SEV encryption in " Joerg Roedel
2021-02-10 16:25 ` Dave Hansen
2021-02-10 16:46 ` Joerg Roedel
2021-02-10 16:47 ` Dave Hansen
2021-02-10 20:44 ` Tom Lendacky
2021-03-02 19:43 ` Borislav Petkov
2021-03-09 10:02 ` Joerg Roedel
2021-02-10 10:21 ` [PATCH 7/7] x86/sev-es: Replace open-coded hlt-loops with sev_es_terminate() Joerg Roedel
2021-02-10 14:58 ` [PATCH 0/7] x86/seves: Support 32-bit boot path and other updates Konrad Rzeszutek Wilk
2021-02-10 15:12 ` Joerg Roedel
2021-02-10 15:19 ` Konrad Rzeszutek Wilk
2021-02-10 15:27 ` Joerg Roedel
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