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x86/hyperv: Avoid erroneously sending IPI to 'self'

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__send_ipi_mask_ex() uses an optimization: when the target CPU mask is
equal to 'cpu_present_mask' it uses 'HV_GENERIC_SET_ALL' format to avoid
converting the specified cpumask to VP_SET. This case was overlooked when
'exclude_self' parameter was added. As the result, a spurious IPI to
'self' can be send.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Fixes: dfb5c1e12c ("x86/hyperv: remove on-stack cpumask from hv_send_ipi_mask_allbutself")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20211006125016.941616-1-vkuznets@redhat.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
This commit is contained in:
Vitaly Kuznetsov 2021-10-06 14:50:16 +02:00 committed by Wei Liu
parent 95a13ee858
commit f5c20e4a5f
1 changed files with 15 additions and 5 deletions
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18
arch/x86/hyperv/hv_apic.c
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@ -122,17 +122,27 @@ static bool __send_ipi_mask_ex(const struct cpumask *mask, int vector,
ipi_arg->reserved = 0; ipi_arg->reserved = 0;
ipi_arg->vp_set.valid_bank_mask = 0; ipi_arg->vp_set.valid_bank_mask = 0;
if (!cpumask_equal(mask, cpu_present_mask)) { /*
* Use HV_GENERIC_SET_ALL and avoid converting cpumask to VP_SET
* when the IPI is sent to all currently present CPUs.
*/
if (!cpumask_equal(mask, cpu_present_mask) || exclude_self) {
ipi_arg->vp_set.format = HV_GENERIC_SET_SPARSE_4K; ipi_arg->vp_set.format = HV_GENERIC_SET_SPARSE_4K;
if (exclude_self) if (exclude_self)
nr_bank = cpumask_to_vpset_noself(&(ipi_arg->vp_set), mask); nr_bank = cpumask_to_vpset_noself(&(ipi_arg->vp_set), mask);
else else
nr_bank = cpumask_to_vpset(&(ipi_arg->vp_set), mask); nr_bank = cpumask_to_vpset(&(ipi_arg->vp_set), mask);
}
if (nr_bank < 0) /*
* 'nr_bank <= 0' means some CPUs in cpumask can't be
* represented in VP_SET. Return an error and fall back to
* native (architectural) method of sending IPIs.
*/
if (nr_bank <= 0)
goto ipi_mask_ex_done; goto ipi_mask_ex_done;
if (!nr_bank) } else {
ipi_arg->vp_set.format = HV_GENERIC_SET_ALL; ipi_arg->vp_set.format = HV_GENERIC_SET_ALL;
}
status = hv_do_rep_hypercall(HVCALL_SEND_IPI_EX, 0, nr_bank, status = hv_do_rep_hypercall(HVCALL_SEND_IPI_EX, 0, nr_bank,
ipi_arg, NULL); ipi_arg, NULL);