RE: [RFC PATCH 4/6] x86/Hyper-V: Allow Hyper-V to inject Hyper-V vectors
From: Michael Kelley <hidden>
Date: 2025-05-14 16:54:40
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From: Tianyu Lan <redacted> Sent: Tuesday, May 6, 2025 6:07 AM
Update Subject prefix to "x86/hyperv".
quoted hunk ↗ jump to hunk
When Secure AVIC is enabled, call Secure AVIC function to allow Hyper-V to inject REENLIGHTENMENT, STIMER0 and CALLBACK vectors. Signed-off-by: Tianyu Lan <redacted> --- arch/x86/hyperv/hv_init.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index ddeb40930bc8..d75df5c3965d 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c@@ -131,6 +131,18 @@ static int hv_cpu_init(unsigned int cpu) wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64); } + /* Allow Hyper-V vector to be injected from Hypervisor. */ + if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) + x2apic_savic_update_vector(cpu, + HYPERV_REENLIGHTENMENT_VECTOR, true);
This will allow Hyper-V to submit the re-enlightenment interrupt on any vCPU, even though the Linux guest has programmed the interrupt to only arrive to a particular vCPU. That selected vCPU is set up in set_hv_tscchange_cb(), and maintained in clear_hv_tscchange_cb() and in hv_cpu_die(). I'm not super familiar with the re-enlightenment code, but I don't see a problem if Hyper-V sends the interrupt on an unexpected vCPU. So it's probably OK to enable this interrupt vector on all vCPUs.
+ + if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) + x2apic_savic_update_vector(cpu, + HYPERV_STIMER0_VECTOR, true); + + x2apic_savic_update_vector(cpu, HYPERVISOR_CALLBACK_VECTOR, true);
This is redundant with Patch 3 of your patch set. In Patch 3, vmbus_interrupt is set to HYPERVISOR_CALLBACK_VECTOR.
+ + return hyperv_init_ghcb(); } -- 2.25.1