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| author | Brijesh Singh <brijesh.singh@amd.com> | 2018-09-14 15:45:58 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-09-15 20:48:45 +0200 |
| commit | b3f0907c71e006e12fde74ea9a745b6096b6f90f (patch) | |
| tree | db20afaf037c1228abafd1e2b6718f68698f0d35 /arch/x86/include | |
| parent | Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/ker... (diff) | |
| download | linux-b3f0907c71e006e12fde74ea9a745b6096b6f90f.tar.xz linux-b3f0907c71e006e12fde74ea9a745b6096b6f90f.zip | |
x86/mm: Add .bss..decrypted section to hold shared variables
kvmclock defines few static variables which are shared with the
hypervisor during the kvmclock initialization.
When SEV is active, memory is encrypted with a guest-specific key, and
if the guest OS wants to share the memory region with the hypervisor
then it must clear the C-bit before sharing it.
Currently, we use kernel_physical_mapping_init() to split large pages
before clearing the C-bit on shared pages. But it fails when called from
the kvmclock initialization (mainly because the memblock allocator is
not ready that early during boot).
Add a __bss_decrypted section attribute which can be used when defining
such shared variable. The so-defined variables will be placed in the
.bss..decrypted section. This section will be mapped with C=0 early
during boot.
The .bss..decrypted section has a big chunk of memory that may be unused
when memory encryption is not active, free it when memory encryption is
not active.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Radim Krčmář<rkrcmar@redhat.com>
Cc: kvm@vger.kernel.org
Link: https://lkml.kernel.org/r/1536932759-12905-2-git-send-email-brijesh.singh@amd.com
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/mem_encrypt.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h index c0643831706e..616f8e637bc3 100644 --- a/arch/x86/include/asm/mem_encrypt.h +++ b/arch/x86/include/asm/mem_encrypt.h @@ -48,10 +48,13 @@ int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size); /* Architecture __weak replacement functions */ void __init mem_encrypt_init(void); +void __init mem_encrypt_free_decrypted_mem(void); bool sme_active(void); bool sev_active(void); +#define __bss_decrypted __attribute__((__section__(".bss..decrypted"))) + #else /* !CONFIG_AMD_MEM_ENCRYPT */ #define sme_me_mask 0ULL @@ -77,6 +80,8 @@ early_set_memory_decrypted(unsigned long vaddr, unsigned long size) { return 0; static inline int __init early_set_memory_encrypted(unsigned long vaddr, unsigned long size) { return 0; } +#define __bss_decrypted + #endif /* CONFIG_AMD_MEM_ENCRYPT */ /* @@ -88,6 +93,8 @@ early_set_memory_encrypted(unsigned long vaddr, unsigned long size) { return 0; #define __sme_pa(x) (__pa(x) | sme_me_mask) #define __sme_pa_nodebug(x) (__pa_nodebug(x) | sme_me_mask) +extern char __start_bss_decrypted[], __end_bss_decrypted[], __start_bss_decrypted_unused[]; + #endif /* __ASSEMBLY__ */ #endif /* __X86_MEM_ENCRYPT_H__ */ |