| Message ID | 20241009154953.1073471-1-seanjc@google.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | KVM: selftests: Morph max_guest_mem to mmu_stress | expand |
On Wed, 09 Oct 2024 08:49:39 -0700, Sean Christopherson wrote: > The main purpose of this series is to convert the max_guest_memory_test > into a more generic mmu_stress_test. The basic gist of the "conversion" > is to have the test do mprotect() on guest memory while vCPUs are > accessing said memory, e.g. to verify KVM and mmu_notifiers are working > as intended. > > Patches 1-4 are a somewhat unexpected side quest. The original plan was > that patch 3 would be a single patch, but things snowballed. > > [...] Applied to kvm-x86 selftests, with the typo fixup pointed out by James. Thanks! [01/14] KVM: Move KVM_REG_SIZE() definition to common uAPI header https://github.com/kvm-x86/linux/commit/5e07fd0bf516 [02/14] KVM: selftests: Disable strict aliasing https://github.com/kvm-x86/linux/commit/d1ce2bcd8d2e [03/14] KVM: selftests: Return a value from vcpu_get_reg() instead of using an out-param https://github.com/kvm-x86/linux/commit/5c6c7b71a45c [04/14] KVM: selftests: Assert that vcpu_{g,s}et_reg() won't truncate https://github.com/kvm-x86/linux/commit/6aa2df3eb90b [05/14] KVM: selftests: Check for a potential unhandled exception iff KVM_RUN succeeded https://github.com/kvm-x86/linux/commit/be9f2746d20b [06/14] KVM: selftests: Rename max_guest_memory_test to mmu_stress_test https://github.com/kvm-x86/linux/commit/06694f27cfcc [07/14] KVM: selftests: Only muck with SREGS on x86 in mmu_stress_test https://github.com/kvm-x86/linux/commit/8556ce365a07 [08/14] KVM: selftests: Compute number of extra pages needed in mmu_stress_test https://github.com/kvm-x86/linux/commit/c7b7876ac5d4 [09/14] KVM: sefltests: Explicitly include ucall_common.h in mmu_stress_test.c https://github.com/kvm-x86/linux/commit/a657856469e1 [10/14] KVM: selftests: Enable mmu_stress_test on arm64 https://github.com/kvm-x86/linux/commit/1e53cde06102 [11/14] KVM: selftests: Use vcpu_arch_put_guest() in mmu_stress_test https://github.com/kvm-x86/linux/commit/8630563012b9 [12/14] KVM: selftests: Precisely limit the number of guest loops in mmu_stress_test https://github.com/kvm-x86/linux/commit/3d4585c220dc [13/14] KVM: selftests: Add a read-only mprotect() phase to mmu_stress_test https://github.com/kvm-x86/linux/commit/eaafeebca75a [14/14] KVM: selftests: Verify KVM correctly handles mprotect(PROT_READ) https://github.com/kvm-x86/linux/commit/a3cd5c187742 -- https://github.com/kvm-x86/linux/tree/next
On Thu, Oct 31, 2024, Sean Christopherson wrote: > On Wed, 09 Oct 2024 08:49:39 -0700, Sean Christopherson wrote: > > The main purpose of this series is to convert the max_guest_memory_test > > into a more generic mmu_stress_test. The basic gist of the "conversion" > > is to have the test do mprotect() on guest memory while vCPUs are > > accessing said memory, e.g. to verify KVM and mmu_notifiers are working > > as intended. > > > > Patches 1-4 are a somewhat unexpected side quest. The original plan was > > that patch 3 would be a single patch, but things snowballed. > > > > [...] > > Applied to kvm-x86 selftests, with the typo fixup pointed out by James. Thanks! > > [01/14] KVM: Move KVM_REG_SIZE() definition to common uAPI header > https://github.com/kvm-x86/linux/commit/5e07fd0bf516 > [02/14] KVM: selftests: Disable strict aliasing > https://github.com/kvm-x86/linux/commit/d1ce2bcd8d2e > [03/14] KVM: selftests: Return a value from vcpu_get_reg() instead of using an out-param > https://github.com/kvm-x86/linux/commit/5c6c7b71a45c > [04/14] KVM: selftests: Assert that vcpu_{g,s}et_reg() won't truncate > https://github.com/kvm-x86/linux/commit/6aa2df3eb90b > [05/14] KVM: selftests: Check for a potential unhandled exception iff KVM_RUN succeeded > https://github.com/kvm-x86/linux/commit/be9f2746d20b > [06/14] KVM: selftests: Rename max_guest_memory_test to mmu_stress_test > https://github.com/kvm-x86/linux/commit/06694f27cfcc > [07/14] KVM: selftests: Only muck with SREGS on x86 in mmu_stress_test > https://github.com/kvm-x86/linux/commit/8556ce365a07 > [08/14] KVM: selftests: Compute number of extra pages needed in mmu_stress_test > https://github.com/kvm-x86/linux/commit/c7b7876ac5d4 > [09/14] KVM: sefltests: Explicitly include ucall_common.h in mmu_stress_test.c > https://github.com/kvm-x86/linux/commit/a657856469e1 > [10/14] KVM: selftests: Enable mmu_stress_test on arm64 > https://github.com/kvm-x86/linux/commit/1e53cde06102 > [11/14] KVM: selftests: Use vcpu_arch_put_guest() in mmu_stress_test > https://github.com/kvm-x86/linux/commit/8630563012b9 > [12/14] KVM: selftests: Precisely limit the number of guest loops in mmu_stress_test > https://github.com/kvm-x86/linux/commit/3d4585c220dc > [13/14] KVM: selftests: Add a read-only mprotect() phase to mmu_stress_test > https://github.com/kvm-x86/linux/commit/eaafeebca75a > [14/14] KVM: selftests: Verify KVM correctly handles mprotect(PROT_READ) > https://github.com/kvm-x86/linux/commit/a3cd5c187742 As mentioned later in the thread[*], I dropped this series from the 6.13 queue and will instead target 6.14. I did however grab the no-strict-aliasing fix for 6.12, and tagged it for stable. There's no reason to wait to land that commit, and I definitely have no desire to ever debug that mess again. [02/14] KVM: selftests: Disable strict aliasing https://github.com/kvm-x86/linux/commit/5b188cc4866a [*] https://lore.kernel.org/all/ZyT61FF0-g8gKZfc@google.com
The main purpose of this series is to convert the max_guest_memory_test into a more generic mmu_stress_test. The basic gist of the "conversion" is to have the test do mprotect() on guest memory while vCPUs are accessing said memory, e.g. to verify KVM and mmu_notifiers are working as intended. Patches 1-4 are a somewhat unexpected side quest. The original plan was that patch 3 would be a single patch, but things snowballed. Patch 3 reworks vcpu_get_reg() to return a value instead of using an out-param. This is the entire motivation for including these patches; having to define a variable just to bump the program counter on arm64 annoyed me. Patch 4 adds hardening to vcpu_{g,s}et_reg() to detect potential truncation, as KVM's uAPI allows for registers greater than the 64 bits that are supported in the "outer" selftests APIs ((vcpu_set_reg() takes a u64, vcpu_get_reg() now returns a u64). Patch 1 is a change to KVM's uAPI headers to move the KVM_REG_SIZE definition to common code so that the selftests side of things doesn't need #ifdefs to implement the hardening in patch 4. Patch 2 is the truly unexpected part. With the vcpu_get_reg() rework, arm64's vpmu_counter_test fails when compiled with gcc-13, and on gcc-11 with an added "noinline". Long story short, selftests are being compiled with strict aliasing enabled, which allows the compiler to optimize away "u64 *" => "uint64_t *" casts as u64 (unsigned long long) and uint64_t (unsigned long) are technically not aliases of each other. *sigh* v3: - Rebased onto v6.12-rc2. - Disable strict aliasing to fix the PMCR snafu. - Collect reviews. [Drew] - Minor changelog fixes. [Drew] - Include ucall_common.h to prep for RISC-V. [Drew] v2: - Rebase onto kvm/next. - Add the aforementioned vcpu_get_reg() changes/disaster. - Actually add arm64 support for the fancy mprotect() testcase (I did this before v1, but managed to forget to include the changes when posting). - Emit "mov %rax, (%rax)" on x86. [James] - Add a comment to explain the fancy mprotect() vs. vCPUs logic. - Drop the KVM x86 patches (applied and/or will be handled separately). v1: https://lore.kernel.org/all/20240809194335.1726916-1-seanjc@google.com Sean Christopherson (14): KVM: Move KVM_REG_SIZE() definition to common uAPI header KVM: selftests: Disable strict aliasing KVM: selftests: Return a value from vcpu_get_reg() instead of using an out-param KVM: selftests: Assert that vcpu_{g,s}et_reg() won't truncate KVM: selftests: Check for a potential unhandled exception iff KVM_RUN succeeded KVM: selftests: Rename max_guest_memory_test to mmu_stress_test KVM: selftests: Only muck with SREGS on x86 in mmu_stress_test KVM: selftests: Compute number of extra pages needed in mmu_stress_test KVM: sefltests: Explicitly include ucall_common.h in mmu_stress_test.c KVM: selftests: Enable mmu_stress_test on arm64 KVM: selftests: Use vcpu_arch_put_guest() in mmu_stress_test KVM: selftests: Precisely limit the number of guest loops in mmu_stress_test KVM: selftests: Add a read-only mprotect() phase to mmu_stress_test KVM: selftests: Verify KVM correctly handles mprotect(PROT_READ) arch/arm64/include/uapi/asm/kvm.h | 3 - arch/riscv/include/uapi/asm/kvm.h | 3 - include/uapi/linux/kvm.h | 4 + tools/testing/selftests/kvm/Makefile | 11 +- .../selftests/kvm/aarch64/aarch32_id_regs.c | 10 +- .../selftests/kvm/aarch64/debug-exceptions.c | 4 +- .../selftests/kvm/aarch64/hypercalls.c | 6 +- .../selftests/kvm/aarch64/no-vgic-v3.c | 2 +- .../testing/selftests/kvm/aarch64/psci_test.c | 6 +- .../selftests/kvm/aarch64/set_id_regs.c | 18 +- .../kvm/aarch64/vpmu_counter_access.c | 19 +- .../testing/selftests/kvm/include/kvm_util.h | 10 +- .../selftests/kvm/lib/aarch64/processor.c | 8 +- tools/testing/selftests/kvm/lib/kvm_util.c | 3 +- .../selftests/kvm/lib/riscv/processor.c | 66 +++---- ..._guest_memory_test.c => mmu_stress_test.c} | 162 ++++++++++++++++-- .../testing/selftests/kvm/riscv/arch_timer.c | 2 +- .../testing/selftests/kvm/riscv/ebreak_test.c | 2 +- .../selftests/kvm/riscv/sbi_pmu_test.c | 2 +- tools/testing/selftests/kvm/s390x/resets.c | 2 +- tools/testing/selftests/kvm/steal_time.c | 3 +- 21 files changed, 241 insertions(+), 105 deletions(-) rename tools/testing/selftests/kvm/{max_guest_memory_test.c => mmu_stress_test.c} (60%) base-commit: 8cf0b93919e13d1e8d4466eb4080a4c4d9d66d7b