linux/virt/kvm
Sean Christopherson e027ba1b83 KVM: Clean up coalesced MMIO ring full check
Fold coalesced_mmio_has_room() into its sole caller, coalesced_mmio_write(),
as it's really just a single line of code, has a goofy return value, and
is unnecessarily brittle.

E.g. if coalesced_mmio_has_room() were to check ring->last directly, or
the caller failed to use READ_ONCE(), KVM would be susceptible to TOCTOU
attacks from userspace.

Opportunistically add a comment explaining why on earth KVM leaves one
entry free, which may not be obvious to readers that aren't familiar with
ring buffers.

No functional change intended.

Reviewed-by: Ilias Stamatis <ilstam@amazon.com>
Cc: Paul Durrant <paul@xen.org>
Link: https://lore.kernel.org/r/20240828181446.652474-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
2024-08-29 19:38:33 -07:00
..
async_pf.c Revert "KVM: async_pf: avoid recursive flushing of work items" 2024-06-03 08:55:55 -07:00
async_pf.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504 2019-06-19 17:09:56 +02:00
binary_stats.c KVM: stats: remove dead stores 2021-08-13 03:35:15 -04:00
coalesced_mmio.c KVM: Clean up coalesced MMIO ring full check 2024-08-29 19:38:33 -07:00
coalesced_mmio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dirty_ring.c KVM: Discard zero mask with function kvm_dirty_ring_reset 2024-06-20 17:20:11 -04:00
eventfd.c KVM: eventfd: Use synchronize_srcu_expedited() on shutdown 2024-08-13 12:09:35 -04:00
guest_memfd.c KVM: guest_memfd: abstract how prepared folios are recorded 2024-07-26 14:46:15 -04:00
irqchip.c KVM: Setup empty IRQ routing when creating a VM 2024-06-11 14:18:34 -07:00
Kconfig KVM: rename CONFIG_HAVE_KVM_GMEM_* to CONFIG_HAVE_KVM_ARCH_GMEM_* 2024-07-26 14:46:14 -04:00
kvm_main.c KVM: x86: Disallow read-only memslots for SEV-ES and SEV-SNP (and TDX) 2024-08-14 12:28:24 -04:00
kvm_mm.h KVM: Drop unused @may_block param from gfn_to_pfn_cache_invalidate_start() 2024-04-11 12:58:53 -07:00
Makefile.kvm KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory 2023-11-14 08:01:03 -05:00
pfncache.c KVM: Validate hva in kvm_gpc_activate_hva() to fix __kvm_gpc_refresh() WARN 2024-06-28 08:31:46 -07:00
vfio.c KVM: Treat the device list as an rculist 2024-04-25 13:19:55 +01:00
vfio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00