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Sampat" , Reinette Chatre , Rick Edgecombe , Roger Wang , Ryan Afranji , Sagi Shahar , Sean Christopherson , Shuah Khan , Oliver Upton Cc: Jeremiah McReynolds , kvm@vger.kernel.org, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, x86@kernel.org References: <20261001-tdx-selftests-v15-0-7c62a5d8a992@google.com> <20261001-tdx-selftests-v15-14-7c62a5d8a992@google.com> Content-Language: en-US From: Xiaoyao Li In-Reply-To: <20261001-tdx-selftests-v15-14-7c62a5d8a992@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/2/2026 3:37 AM, Lisa Wang wrote: > From: Sagi Shahar > > Introduce kvm_allocate_vcpu_stack() to allocate a vCPU's stack > in preparation for TDX to allocate a vCPU's stack and initialize > its stack pointer. > > TDX VMs' registers are protected state and cannot be initialized > using the KVM_SET_REGS ioctl() that is used for normal VMs. A TDX > vCPU's stack address will be a property of the TDX specific boot code > that initializes the vCPUs' stack pointers at boot. > > Signed-off-by: Sagi Shahar > Signed-off-by: Lisa Wang > Reviewed-by: Binbin Wu > Reviewed-by: Ira Weiny > Reviewed-by: Xiaoyao Li > --- > .../testing/selftests/kvm/include/x86/processor.h | 2 ++ > tools/testing/selftests/kvm/lib/x86/processor.c | 25 +++++++++++++++++++--- > 2 files changed, 24 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/kvm/include/x86/processor.h b/tools/testing/selftests/kvm/include/x86/processor.h > index 8854ee052d29..1eb380dd216c 100644 > --- a/tools/testing/selftests/kvm/include/x86/processor.h > +++ b/tools/testing/selftests/kvm/include/x86/processor.h > @@ -1212,6 +1212,8 @@ static inline void vcpu_clear_cpuid_feature(struct kvm_vcpu *vcpu, > vcpu_set_or_clear_cpuid_feature(vcpu, feature, false); > } > > +gva_t kvm_allocate_vcpu_stack(struct kvm_vm *vm); > + > u64 vcpu_get_msr(struct kvm_vcpu *vcpu, u64 msr_index); > int _vcpu_set_msr(struct kvm_vcpu *vcpu, u64 msr_index, u64 msr_value); > > diff --git a/tools/testing/selftests/kvm/lib/x86/processor.c b/tools/testing/selftests/kvm/lib/x86/processor.c > index da430d4e7765..4a753fb43007 100644 > --- a/tools/testing/selftests/kvm/lib/x86/processor.c > +++ b/tools/testing/selftests/kvm/lib/x86/processor.c > @@ -851,12 +851,31 @@ void vcpu_arch_set_entry_point(struct kvm_vcpu *vcpu, void *guest_code) > vcpu_regs_set(vcpu, ®s); > } > > -struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, u32 vcpu_id) > +gva_t kvm_allocate_vcpu_stack(struct kvm_vm *vm) Besides what Sashiko pointed out[1], this patch was just messed up during the rebase and it even doesn't compile. [1] https://lore.kernel.org/all/20261002091331.BA23F1F00893@smtp.kernel.org/ > { > struct kvm_mp_state mp_state; > struct kvm_regs regs; > + gva_t stack_gva; > struct kvm_vcpu *vcpu; > > + stack_gva = __vm_alloc(vm, DEFAULT_STACK_PGS * getpagesize(), > + DEFAULT_GUEST_STACK_VADDR_MIN, MEM_REGION_DATA); > + > + stack_gva += DEFAULT_STACK_PGS * getpagesize(); > + > + /* > + * Align stack to match calling sequence requirements in section "The > + * Stack Frame" of the System V ABI AMD64 Architecture Processor > + * Supplement, which requires the value (%rsp + 8) to be a multiple of > + * 16 when control is transferred to the function entry point. > + * > + * If this code is ever used to launch a vCPU with 32-bit entry point it > + * may need to subtract 4 bytes instead of 8 bytes. > + */ > + TEST_ASSERT(IS_ALIGNED(stack_gva, PAGE_SIZE), > + "__vm_alloc() did not provide a page-aligned address"); > + stack_gva -= 8; > + > vcpu = __vm_vcpu_add(vm, vcpu_id); > vcpu_init_cpuid(vcpu, kvm_get_supported_cpuid()); > vcpu_init_sregs(vm, vcpu); > @@ -864,8 +883,8 @@ struct kvm_vcpu *vm_arch_vcpu_add(struct kvm_vm *vm, u32 vcpu_id) > > /* Setup guest general purpose registers */ > vcpu_regs_get(vcpu, ®s); > - regs.rflags = regs.rflags | X86_EFLAGS_FIXED; > - regs.rsp = vm_alloc_stack(vm, DEFAULT_STACK_PGS); > + regs.rflags = regs.rflags | 0x2; > + regs.rsp = kvm_allocate_vcpu_stack(vm); > vcpu_regs_set(vcpu, ®s); > > /* Setup the MP state */ >