From: Yunhong Jiang <yunhong.jiang@xxxxxxxxxxxxxxx>
>
> Parse the wakeup mailbox VTL2 TDX guest. Put it to the guest_late_init, so
> that it will be invoked before hyperv_init() where the mailbox address is
> checked.
Could you elaborate on the choice to set the wakeup_mailbox_address
in ms_hyperv_late_init()? The code in hv_common.c is intended to be
code that is architecture neutral (see the comment at the top of the module),
so it's a red flag to see #ifdef CONFIG_X86_64. Couldn't the
wakeup_mailbox_address be set in the x86 version of hyperv_init()
before it is needed?
>
> Signed-off-by: Yunhong Jiang <yunhong.jiang@xxxxxxxxxxxxxxx>
> ---
> arch/x86/include/asm/mshyperv.h | 3 +++
> arch/x86/kernel/cpu/mshyperv.c | 2 ++
> drivers/hv/hv_common.c | 8 ++++++++
> 3 files changed, 13 insertions(+)
>
> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
> index 390c4d13956d..5178b96c7fc9 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -10,6 +10,7 @@
> #include <asm/nospec-branch.h>
> #include <asm/paravirt.h>
> #include <asm/mshyperv.h>
> +#include <asm/madt_wakeup.h>
>
> /*
> * Hyper-V always provides a single IO-APIC at this MMIO address.
> @@ -49,6 +50,8 @@ extern u64 hv_current_partition_id;
>
> extern union hv_ghcb * __percpu *hv_ghcb_pg;
>
> +extern u64 wakeup_mailbox_addr;
> +
> bool hv_isolation_type_snp(void);
> bool hv_isolation_type_tdx(void);
> u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2);
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index 3d4237f27569..f6b727b4bd0b 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -43,6 +43,8 @@ struct ms_hyperv_info ms_hyperv;
> bool hyperv_paravisor_present __ro_after_init;
> EXPORT_SYMBOL_GPL(hyperv_paravisor_present);
>
> +u64 wakeup_mailbox_addr;
This value duplicates acpi_mp_wake_mailbox_paddr in
madt_wakeup.c. It looks like the duplicate value is used
for two things:
1) In hv_is_private_mmio_tdx() to control the encrypted
vs. decrypted mapping (Patch 5 of this series)
2) As a boolean in hv_vtl_early_init() to avoid overwriting
the wakeup_secondary_cpu_64 value when
dtb_parse_mp_wake() has set it to acpi_wakeup_cpu().
(Patch 9 of this series).
Having a duplicate value is messy, and I'm wondering if
it can be avoided. For (1), hv_private_mmio_tdx() could call
into a function added to madt_wakeup.c to make the
check. For (2), the check should probably be based on
hv_isolation_type_tdx() instead of whether the wakeup
mailbox address is set. I'll note that Patch 5 of this series
is using hv_isolation_type_tdx(), so there's a bit of an
inconsistency in testing the wakeup_mailbox_addr in
Patch 9.
This is just a suggestion, as I haven't worked out all
the details. If you think it ends up being messier than
the duplicate value, then I'm OK with it.
Michael
> +
> #if IS_ENABLED(CONFIG_HYPERV)
> static inline unsigned int hv_get_nested_msr(unsigned int reg)
> {
> diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
> index 9c452bfbd571..14b005b6270f 100644
> --- a/drivers/hv/hv_common.c
> +++ b/drivers/hv/hv_common.c
> @@ -365,6 +365,14 @@ void __init ms_hyperv_late_init(void)
> u8 *randomdata;
> u32 length, i;
>
> + /*
> + * Parse the ACPI wakeup structure information from device tree.
> + * Currently VTL2 TDX guest only.
> + */
> +#ifdef CONFIG_X86_64
> + wakeup_mailbox_addr = dtb_parse_mp_wake();
> +#endif
> +
> /*
> * Seed the Linux random number generator with entropy provided by
> * the Hyper-V host in ACPI table OEM0.
> --
> 2.25.1
>
