From: Roman Kisel <rom...@linux.microsoft.com> Sent: Monday, April 28, 2025
11:27 AM
>
> To start an application processor in SNP-isolated guest, a hypercall
> is used that takes a virtual processor index. The hv_snp_boot_ap()
> function uses that START_VP hypercall but passes as VP index to it
> what it receives as a wakeup_secondary_cpu_64 callback: the APIC ID.
>
> As those two aren't generally interchangeable, that may lead to hung
> APs if the VP index and the APIC ID don't match up.
>
> Update the parameter names to avoid confusion as to what the parameter
> is. Use the APIC ID to the VP index conversion to provide the correct
> input to the hypercall.
>
> Cc: sta...@vger.kernel.org
> Fixes: 44676bb9d566 ("x86/hyperv: Add smp support for SEV-SNP guest")
> Signed-off-by: Roman Kisel <rom...@linux.microsoft.com>
> ---
> [V3]
> - Removed the misleading comment about the APIC ID and VP indices.
> - Removed the not sufficiently founded if statement that was added
> to the previous version of the patch to avoid the O(n) time
> complexity.
> I'll follow up with a separate patch to address that as that pattern
> has crept into other places in the code in the AP wakeup path.
> - Fixed the logging message to use the "VP index" terminology
> consistently.
> ** Thank you, Michael! **
>
> [V2]
>
> https://lore.kernel.org/linux-hyperv/20250425213512.1837061-1-rom...@linux.microsoft.com/
> - Fixed the terminology in the patch and other code to use
> the term "VP index" consistently
> ** Thank you, Michael! **
>
> - Missed not enabling the SNP-SEV options in the local testing,
> and sent a patch that breaks the build.
> ** Thank you, Saurabh! **
>
> - Added comments and getting the Linux kernel CPU number from
> the available data.
>
> [V1]
>
> https://lore.kernel.org/linux-hyperv/20250424215746.467281-1-rom...@linux.microsoft.com/
> ---
> arch/x86/hyperv/hv_init.c | 33 +++++++++++++++++++++++++
> arch/x86/hyperv/hv_vtl.c | 44 +++++----------------------------
> arch/x86/hyperv/ivm.c | 22 +++++++++++++++--
> arch/x86/include/asm/mshyperv.h | 6 +++--
> include/hyperv/hvgdk_mini.h | 2 +-
> 5 files changed, 64 insertions(+), 43 deletions(-)
Thanks for fixing the terminology, in addition to fixing the bug that is your
original
purpose for the patch.
Reviewed-by: Michael Kelley <mhkli...@outlook.com>
