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Revision c15e0ae42c8e5a61e9aca8aac920517cf7b3e94e authored by Li RongQing on 09 March 2022, 08:35:44 UTC, committed by Paolo Bonzini on 02 April 2022, 09:37:27 UTC 
KVM: x86: fix sending PV IPI
 
If apic_id is less than min, and (max - apic_id) is greater than
KVM_IPI_CLUSTER_SIZE, then the third check condition is satisfied but
the new apic_id does not fit the bitmask.  In this case __send_ipi_mask
should send the IPI.

This is mostly theoretical, but it can happen if the apic_ids on three
iterations of the loop are for example 1, KVM_IPI_CLUSTER_SIZE, 0.

Fixes: aaffcfd1e82 ("KVM: X86: Implement PV IPIs in linux guest")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Message-Id: <1646814944-51801-1-git-send-email-lirongqing@baidu.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 parent 2a8859f
Raw File
pgalloc-track.h 
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PGALLOC_TRACK_H
#define _LINUX_PGALLOC_TRACK_H

#if defined(CONFIG_MMU)
static inline p4d_t *p4d_alloc_track(struct mm_struct *mm, pgd_t *pgd,
				     unsigned long address,
				     pgtbl_mod_mask *mod_mask)
{
	if (unlikely(pgd_none(*pgd))) {
		if (__p4d_alloc(mm, pgd, address))
			return NULL;
		*mod_mask |= PGTBL_PGD_MODIFIED;
	}

	return p4d_offset(pgd, address);
}

static inline pud_t *pud_alloc_track(struct mm_struct *mm, p4d_t *p4d,
				     unsigned long address,
				     pgtbl_mod_mask *mod_mask)
{
	if (unlikely(p4d_none(*p4d))) {
		if (__pud_alloc(mm, p4d, address))
			return NULL;
		*mod_mask |= PGTBL_P4D_MODIFIED;
	}

	return pud_offset(p4d, address);
}

static inline pmd_t *pmd_alloc_track(struct mm_struct *mm, pud_t *pud,
				     unsigned long address,
				     pgtbl_mod_mask *mod_mask)
{
	if (unlikely(pud_none(*pud))) {
		if (__pmd_alloc(mm, pud, address))
			return NULL;
		*mod_mask |= PGTBL_PUD_MODIFIED;
	}

	return pmd_offset(pud, address);
}
#endif /* CONFIG_MMU */

#define pte_alloc_kernel_track(pmd, address, mask)			\
	((unlikely(pmd_none(*(pmd))) &&					\
	  (__pte_alloc_kernel(pmd) || ({*(mask)|=PGTBL_PMD_MODIFIED;0;})))?\
		NULL: pte_offset_kernel(pmd, address))

#endif /* _LINUX_PGALLOC_TRACK_H */
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