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Date:   Sat, 13 Jun 2020 11:24:08 -0400
From:   Qian Cai <cai@lca.pw>
To:     thomas.lendacky@amd.com, brijesh.singh@amd.com
Cc:     tglx@linutronix.de, bp@suse.de, glider@google.com,
        peterz@infradead.org, dvyukov@google.com,
        kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org
Subject: AMD SME + KASAN = doom
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CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=y + KASAN (inline) will reset
the host right away after those lines on linux-next (the mainline has
the same problem when I tested a while back, so it seems never work),

Wrong EFI loader signature.
early console in extract_kernel
input_data: 0x000000000c7ad3a8
input_len: 0x0000000000aa5f4c
output: 0x0000000001000000
output_len: 0x000000000c1808cc
kernel_total_size: 0x000000000b62c000
needed_size: 0x000000000c200000
trampoline_32bit: 0x000000000008a000
booted via startup_32()
Physical KASLR using RDRAND RDTSC...
Virtual KASLR using RDRAND RDTSC...

Decompressing Linux... Parsing ELF... Performing relocations... done.
Booting the kernel.

The .config (plus CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=y):
https://raw.githubusercontent.com/cailca/linux-mm/master/x86.config

Reproduced on several systems including,

HPE DL385 G10
AMD EPYC 7301 16-Core Processor

Dell PowerEdge R6415
AMD EPYC 7401P 24-Core Processor

Even on one of the HPE DL385 G10, it is able to boot but NO such
message, "AMD Secure Memory Encryption (SME) active"

Set KASAN=n will boot and has the above message at least on those Dell
systems.