diff options
| author | Yosry Ahmed <yosry@kernel.org> | 2026-07-28 17:42:21 +0000 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2026-07-29 05:45:26 -0700 |
| commit | 53f4ad49d76b516f5d235ea10b727b2d548b0218 (patch) | |
| tree | a950539984bdf8e471f9ea00145539d3cc8fbce9 /tools/testing/selftests/kvm/lib | |
| parent | 9be54a82656cfda5eab0f4f25354be6075f8467d (diff) | |
KVM: selftests: Fix RAX and RFLAGS VMCB offsets when running L2
The offsets used (0x170 and 0x1f8) are offsets within vmcb_save_area,
not vmcb. The correct offsets should include the base of vmcb_save_area
within vmcb (which is 0x400 -- so 0x570 and 0x5f8).
Instead of just correcting the offsets, use vmcb->save.rax and
vmcb->save.rflags as parameters to the asm block and avoid hardcoding
offsets completely. While at it, also use guest_regs.rax directly
instead of assuming it's at offset 0 of guest_regs.
Note: "+m" must be used for vmcb_rax and vmcb_rflags, as caching those
fields in registers would be wrong as the underlying KVM will update
them in memory.
The same problem was recently fixed (differently) for kvm-unit-tests
[1].
[1]https://lore.kernel.org/all/20260521092311.86030-1-pbonzini@redhat.com/
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260518202514.2037078-1-yosry%40kernel.org?part=1
Signed-off-by: Yosry Ahmed <yosry@kernel.org>
Link: https://patch.msgid.link/20260728174232.2423257-3-yosry@kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'tools/testing/selftests/kvm/lib')
| -rw-r--r-- | tools/testing/selftests/kvm/lib/x86/svm.c | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/tools/testing/selftests/kvm/lib/x86/svm.c b/tools/testing/selftests/kvm/lib/x86/svm.c index 1445b890986f..766d15f1d534 100644 --- a/tools/testing/selftests/kvm/lib/x86/svm.c +++ b/tools/testing/selftests/kvm/lib/x86/svm.c @@ -164,19 +164,22 @@ void run_guest(struct vmcb *vmcb, u64 vmcb_gpa) { asm volatile ( "vmload %[vmcb_gpa]\n\t" - "mov rflags, %%r15\n\t" // rflags - "mov %%r15, 0x170(%[vmcb])\n\t" - "mov guest_regs, %%r15\n\t" // rax - "mov %%r15, 0x1f8(%[vmcb])\n\t" + "mov rflags, %%r15\n\t" + "mov %%r15, %[vmcb_rflags]\n\t" + "mov %[guest_regs_rax], %%r15\n\t" + "mov %%r15, %[vmcb_rax]\n\t" LOAD_GPR_C "vmrun %[vmcb_gpa]\n\t" SAVE_GPR_C - "mov 0x170(%[vmcb]), %%r15\n\t" // rflags + "mov %[vmcb_rflags], %%r15\n\t" "mov %%r15, rflags\n\t" - "mov 0x1f8(%[vmcb]), %%r15\n\t" // rax - "mov %%r15, guest_regs\n\t" + "mov %[vmcb_rax], %%r15\n\t" // rax + "mov %%r15, %[guest_regs_rax]\n\t" "vmsave %[vmcb_gpa]\n\t" - : : [vmcb] "r" (vmcb), [vmcb_gpa] "a" (vmcb_gpa) + : [vmcb_rflags] "+m" (vmcb->save.rflags), + [vmcb_rax] "+m" (vmcb->save.rax), + [guest_regs_rax] "+rm" (guest_regs.rax) + : [vmcb_gpa] "a" (vmcb_gpa) : "r15", "memory"); } |