diff options
| author | Michael Kelley <mikelley@microsoft.com> | 2023-03-08 18:40:02 -0800 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2023-03-26 23:42:40 +0200 |
| commit | 88e378d400fa0544d51cf62037e7774d8a4b4379 (patch) | |
| tree | 07da1f613ff1e7d87644b3ee3066d09bd305de28 /arch/x86/kernel/x86_init.c | |
| parent | 0144e3b85d7b42e8a4cda991c0e81f131897457a (diff) | |
x86/ioremap: Add hypervisor callback for private MMIO mapping in coco VM
Current code always maps MMIO devices as shared (decrypted) in a
confidential computing VM. But Hyper-V guest VMs on AMD SEV-SNP with vTOM
use a paravisor running in VMPL0 to emulate some devices, such as the
IO-APIC and TPM. In such a case, the device must be accessed as private
(encrypted) because the paravisor emulates the device at an address below
vTOM, where all accesses are encrypted.
Add a new hypervisor callback to determine if an MMIO address should
be mapped private. The callback allows hypervisor-specific code to handle
any quirks, the use of a paravisor, etc. in determining whether a mapping
must be private. If the callback is not used by a hypervisor, default
to returning "false", which is consistent with normal coco VM behavior.
Use this callback as another special case to check for when doing
ioremap(). Just checking the starting address is sufficient as an
ioremap range must be all private or all shared.
Also make the callback in early boot IO-APIC mapping code that uses the
fixmap.
[ bp: Touchups. ]
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/1678329614-3482-2-git-send-email-mikelley@microsoft.com
Diffstat (limited to 'arch/x86/kernel/x86_init.c')
| -rw-r--r-- | arch/x86/kernel/x86_init.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c index ef80d361b463..95be3831df73 100644 --- a/arch/x86/kernel/x86_init.c +++ b/arch/x86/kernel/x86_init.c @@ -134,6 +134,7 @@ static void enc_status_change_prepare_noop(unsigned long vaddr, int npages, bool static bool enc_status_change_finish_noop(unsigned long vaddr, int npages, bool enc) { return false; } static bool enc_tlb_flush_required_noop(bool enc) { return false; } static bool enc_cache_flush_required_noop(void) { return false; } +static bool is_private_mmio_noop(u64 addr) {return false; } struct x86_platform_ops x86_platform __ro_after_init = { .calibrate_cpu = native_calibrate_cpu_early, @@ -149,6 +150,7 @@ struct x86_platform_ops x86_platform __ro_after_init = { .realmode_reserve = reserve_real_mode, .realmode_init = init_real_mode, .hyper.pin_vcpu = x86_op_int_noop, + .hyper.is_private_mmio = is_private_mmio_noop, .guest = { .enc_status_change_prepare = enc_status_change_prepare_noop, |