[PATCH 0/5] KVM: selftests: Reserve memslot 1 for ucall MMIO

From: Tharit Tangkijwanichakul <tharitt97@gmail.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>
Cc: Shuah Khan <shuah@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Oliver Upton <oupton@kernel.org>,
	Fuad Tabba <fuad.tabba@linux.dev>,
	Joey Gouly <joey.gouly@arm.com>,
	Steffen Eiden <seiden@linux.ibm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Anup Patel <anup@brainfault.org>,
	Atish Patra <atish.patra@linux.dev>,
	Paul Walmsley <pjw@kernel.org>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-kselftest@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
	kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org,
	linux-kernel-mentees@lists.linux.dev, skhan@linuxfoundation.org,
	me@brighamcampbell.com, jkoolstra@xs4all.nl,
	Tharit Tangkijwanichakul <tharitt97@gmail.com>
Subject: [PATCH 0/5] KVM: selftests: Reserve memslot 1 for ucall MMIO
Date: Sat, 17 Oct 2026 18:02:08 +0700	[thread overview]
Message-ID: <20261017110213.46199-1-tharitt97@gmail.com> (raw)

This series addresses the TODO in __vm_create() to reserve memslot 1
for the ucall MMIO region. It introduces a shared base for test
memslots, migrates existing test users, and adds a read-only region to
prevent overlapping allocations.

A regression test verifies overlap rejection and continued ucall
operation.

Testing:
- Intel Core i5-10210U and Rockchip RK3588 (arm64).

These tests are changed but not tested: 
- arm64/sea_to_user.c: not enough memory allocation.
- x86/nested_vmsave_vmload_test.c: requires X86_FEATURE_SVM.
- riscv/sbi_pmu_test.c: riscv hardware unavailability.

The following test failures reproduce on both the unmodified base
<8edffbc1f6272db167037e1a8c49b99e9cd04803> with host kernel 
7.3.0-rc1-gd4b7fb647204 on RK3588 and with this series applied:
- arm64/vgic_its_save.c
- arm64/hypercalls.c

These failures are unchanged by this series.

Tharit Tangkijwanichakul (5):
  KVM: selftests: Introduce a shared base for test memslots
  KVM: selftests: Use the shared memslot base in memslot_perf_test
  KVM: selftests: Use the shared memslot base in memstress
  KVM: selftests: Reserve memslot 1 for the ucall MMIO address
  KVM: selftests: Test protection of the ucall MMIO region

 tools/testing/selftests/kvm/Makefile.kvm      |  1 +
 .../testing/selftests/kvm/arm64/hypercalls.c  |  3 +-
 .../testing/selftests/kvm/arm64/sea_to_user.c |  2 +-
 .../kvm/arm64/stage2_block_transitions.c      |  2 +-
 .../selftests/kvm/arm64/vgic_its_save.c       |  2 +-
 .../selftests/kvm/arm64/vgic_lpi_stress.c     |  2 +-
 tools/testing/selftests/kvm/dirty_log_test.c  |  2 +-
 .../testing/selftests/kvm/guest_memfd_test.c  |  2 +-
 .../testing/selftests/kvm/include/kvm_util.h  |  1 +
 .../testing/selftests/kvm/include/memstress.h |  2 +-
 .../selftests/kvm/kvm_page_table_test.c       |  2 +-
 tools/testing/selftests/kvm/lib/kvm_util.c    | 19 ++++--
 .../testing/selftests/kvm/memslot_perf_test.c | 62 +++++++++++--------
 tools/testing/selftests/kvm/mmu_stress_test.c |  2 +-
 .../selftests/kvm/reserved_slot_test.c        | 61 ++++++++++++++++++
 .../selftests/kvm/riscv/sbi_pmu_test.c        |  3 +-
 tools/testing/selftests/kvm/steal_time.c      |  3 +-
 .../selftests/kvm/x86/nested_dirty_log_test.c |  2 +-
 .../kvm/x86/nested_vmsave_vmload_test.c       |  2 +-
 19 files changed, 128 insertions(+), 47 deletions(-)
 create mode 100644 tools/testing/selftests/kvm/reserved_slot_test.c

-- 
2.53.0