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| author | Brijesh Singh <brijesh.singh@amd.com> | 2017-10-20 09:30:57 -0500 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2017-11-07 15:35:59 +0100 |
| commit | ac26963a1175c813e3ed21c0d2435b083173136e (patch) | |
| tree | 0142c85cd9037d5d790a10d78588409558f26b96 /include | |
| parent | dfaaec9033b80d71056e21cda920752e55f2c514 (diff) | |
| download | linux-next-ac26963a1175c813e3ed21c0d2435b083173136e.tar.gz | |
percpu: Introduce DEFINE_PER_CPU_DECRYPTED
KVM guest defines three per-CPU variables (steal-time, apf_reason, and
kvm_pic_eoi) which are shared between a guest and a hypervisor.
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 (i.e set decrypted) before sharing it.
DEFINE_PER_CPU_DECRYPTED can be used to define the per-CPU variables
which will be shared between a guest and a hypervisor.
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: linux-arch@vger.kernel.org
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: kvm@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Lameter <cl@linux.com>
Link: https://lkml.kernel.org/r/20171020143059.3291-16-brijesh.singh@amd.com
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-generic/vmlinux.lds.h | 19 | ||||
| -rw-r--r-- | include/linux/percpu-defs.h | 15 |
2 files changed, 34 insertions, 0 deletions
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 63e56f6c1877..c58f3805e348 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -778,6 +778,24 @@ #endif /* + * Memory encryption operates on a page basis. Since we need to clear + * the memory encryption mask for this section, it needs to be aligned + * on a page boundary and be a page-size multiple in length. + * + * Note: We use a separate section so that only this section gets + * decrypted to avoid exposing more than we wish. + */ +#ifdef CONFIG_AMD_MEM_ENCRYPT +#define PERCPU_DECRYPTED_SECTION \ + . = ALIGN(PAGE_SIZE); \ + *(.data..percpu..decrypted) \ + . = ALIGN(PAGE_SIZE); +#else +#define PERCPU_DECRYPTED_SECTION +#endif + + +/* * Default discarded sections. * * Some archs want to discard exit text/data at runtime rather than @@ -815,6 +833,7 @@ . = ALIGN(cacheline); \ *(.data..percpu) \ *(.data..percpu..shared_aligned) \ + PERCPU_DECRYPTED_SECTION \ VMLINUX_SYMBOL(__per_cpu_end) = .; /** diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h index 8f16299ca068..2d2096ba1cfe 100644 --- a/include/linux/percpu-defs.h +++ b/include/linux/percpu-defs.h @@ -173,6 +173,21 @@ DEFINE_PER_CPU_SECTION(type, name, "..read_mostly") /* + * Declaration/definition used for per-CPU variables that should be accessed + * as decrypted when memory encryption is enabled in the guest. + */ +#if defined(CONFIG_VIRTUALIZATION) && defined(CONFIG_AMD_MEM_ENCRYPT) + +#define DECLARE_PER_CPU_DECRYPTED(type, name) \ + DECLARE_PER_CPU_SECTION(type, name, "..decrypted") + +#define DEFINE_PER_CPU_DECRYPTED(type, name) \ + DEFINE_PER_CPU_SECTION(type, name, "..decrypted") +#else +#define DEFINE_PER_CPU_DECRYPTED(type, name) DEFINE_PER_CPU(type, name) +#endif + +/* * Intermodule exports for per-CPU variables. sparse forgets about * address space across EXPORT_SYMBOL(), change EXPORT_SYMBOL() to * noop if __CHECKER__. |