From: Yunhong Jiang <yunhong.jiang@xxxxxxxxxxxxxxx> Sent: Tuesday, September 3, 2024 1:19 PM > > On Mon, Sep 02, 2024 at 03:35:13AM +0000, Michael Kelley wrote: > > 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? > > Sure, will try to put it in hyperv_init() before it's 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. > > I think your comment includes two points, the duplicated variables and the > incosistency in the testing. > > Thank you for pointing out the duplication of wakeup_mailbox_addr with > acpi_mp_wake_mailbox_paddr. I didn't realize it. Yes, such duplication should be > avoided and will fix it in next submission. > > Agree the inconsistency in testing wakeup_mailbox_addr and > hv_isolation_type_tdx() is not good. IMHO, the wakeup_mailbox_addr (or the new > function you proposed) is better than hv_isolation_type_tdx(), since the > wakeup_mailbox_addr is more directly related. But hv_vtl_init_platform() > happens before DT parse, thus I have to use the hv_isolation_type_tdx() in it. I > don't have a good idea on how to fix this. > > Thanks > --jyh > I don't think there's a requirement to set the "is_private_mmio" function in hv_vtl_init_platform(). It just needs to be set before acpi_wakeup_cpu() is called, which does the memremap() that will invoke the "is_private_mmio" function to decide whether to map as encrypted or decrypted. So maybe setting the "is_private_mmio" function could be done after dtb_parse_mp_wake() is called in its new location, and you know you have a valid wake mailbox address? Again, I haven't worked out all the details, so this approach might be just as messy, but in a different way. Use your judgment ... :-) Michael
