diff options
| author | Dexuan Cui <decui@microsoft.com> | 2023-08-24 01:07:09 -0700 |
|---|---|---|
| committer | Wei Liu <wei.liu@kernel.org> | 2023-08-25 00:04:57 +0000 |
| commit | 23378295042a4bcaeec350733a4771678e7a1f3a (patch) | |
| tree | 96e4447fe9da4a905966d611f98ace45fb4ea714 /drivers/hv/hyperv_vmbus.h | |
| parent | d3a9d7e49d15316f68f4347f48adcd1665834980 (diff) | |
Drivers: hv: vmbus: Bring the post_msg_page back for TDX VMs with the paravisor
The post_msg_page was removed in
commit 9a6b1a170ca8 ("Drivers: hv: vmbus: Remove the per-CPU post_msg_page")
However, it turns out that we need to bring it back, but only for a TDX VM
with the paravisor: in such a VM, the hyperv_pcpu_input_arg is not decrypted,
but the HVCALL_POST_MESSAGE in such a VM needs a decrypted page as the
hypercall input page: see the comments in hyperv_init() for a detailed
explanation.
Except for HVCALL_POST_MESSAGE and HVCALL_SIGNAL_EVENT, the other hypercalls
in a TDX VM with the paravisor still use hv_hypercall_pg and must use the
hyperv_pcpu_input_arg (which is encrypted in such a VM), when a hypercall
input page is used.
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Tianyu Lan <tiala@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20230824080712.30327-8-decui@microsoft.com
Diffstat (limited to 'drivers/hv/hyperv_vmbus.h')
| -rw-r--r-- | drivers/hv/hyperv_vmbus.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index 55f2086841ae..f6b1e710f805 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -124,6 +124,17 @@ struct hv_per_cpu_context { void *synic_event_page; /* + * The page is only used in hv_post_message() for a TDX VM (with the + * paravisor) to post a messages to Hyper-V: when such a VM calls + * HVCALL_POST_MESSAGE, it can't use the hyperv_pcpu_input_arg (which + * is encrypted in such a VM) as the hypercall input page, because + * the input page for HVCALL_POST_MESSAGE must be decrypted in such a + * VM, so post_msg_page (which is decrypted in hv_synic_alloc()) is + * introduced for this purpose. See hyperv_init() for more comments. + */ + void *post_msg_page; + + /* * Starting with win8, we can take channel interrupts on any CPU; * we will manage the tasklet that handles events messages on a per CPU * basis. |