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I thought you were not happy with the commit message wording/structure. >> x86/apic: Add support to send IPI for Secure AVIC >> >> Secure AVIC hardware only accelerates Self-IPI, i.e. on WRMSR to >> APIC_SELF_IPI and APIC_ICR (with destination shorthand equal to Self) >> registers, hardware takes care of updating the APIC_IRR in the APIC >> backing page of the vCPU. For other IPI types (cross-vCPU, broadcast IPIs), >> software needs to take care of updating the APIC_IRR state of the target >> CPUs and to ensure that the target vCPUs notice the new pending interrupt. >> >> Add new callbacks in the Secure AVIC driver for sending IPI requests. These >> callbacks update the IRR in the target guest vCPU's APIC backing page. To >> ensure that the remote vCPU notices the new pending interrupt, reuse the >> GHCB MSR handling code in vc_handle_msr() to issue APIC_ICR MSR-write GHCB >> protocol event to the hypervisor. For Secure AVIC guests, on APIC_ICR write >> MSR exits, the hypervisor notifies the target vCPU by either sending an AVIC >> doorbell (if target vCPU is running) or by waking up the non-running target >> vCPU. > > But I'll take a definitely better commit message too! :-) > Cool! >> Ok moving it to x2apic_savic.c requires below 4 sev-internal declarations to >> be moved to arch/x86/include/asm/sev.h >> >> struct ghcb_state; >> struct ghcb *__sev_get_ghcb(struct ghcb_state *state); >> void __sev_put_ghcb(struct ghcb_state *state); >> enum es_result sev_es_ghcb_handle_msr(...); > > Well, do you anticipate needing any more sev* facilities for SAVIC? > At this point I do not anticipate adding new functions for new SAVIC features. > If so, you probably should carve them out into arch/x86/coco/sev/savic.c > > If only 4 functions, I guess they're probably still ok in .../sev/core.c > Ok. I will keep them in sev/core.c for now and move to sev/savic.c if anything new comes up in future. >> This comment explains why WRMSR is sufficient for sending SELF_IPI. On >> WRMSR by vCPU, Secure AVIC hardware takes care of updating APIC_IRR in >> backing page. Hardware also ensures that new APIC_IRR state is evaluated >> for new pending interrupts. So, WRMSR is hardware-accelerated. >> >> For non-self-IPI case, software need to do APIC_IRR update and sending of >> wakeup-request/doorbell to the target vCPU. > > Yeah, you need to rewrite it like the commit message above - it needs to say > that upon the MSR write, hw does this and that and therefore accelerates this > type of IPI. > > Then it is clear what you mean by "acceleration." > Got it. Will update. Thanks! - Neeraj > Thx. >