On Wed, Sep 04, 2024 at 02:56:49PM +0000, Michael Kelley wrote: > 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 ... :-) Sorry that I didn't explain clearly. The testing in hv_vtl_init_platform() is not only for the is_private_mmio, but also for the realmode_reserve(), which happens before the DT parse. BTW, I don't know why the trampoline_64.S is put into the real mode blob. I don't find any specific requirement in the code, but I'm not sure if I missed anything. If this dependency is removed, all the TDX guest will benefit. Thank you --jyh > > Michael
