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Bae" , seanjc@google.com Cc: kvm@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, chao.gao@intel.com, Borislav Petkov , Dave Hansen References: <20260512011502.53072-1-chang.seok.bae@intel.com> <20260512011502.53072-7-chang.seok.bae@intel.com> Content-Language: en-US From: Paolo Bonzini Autocrypt: addr=pbonzini@redhat.com; keydata= xsEhBFRCcBIBDqDGsz4K0zZun3jh+U6Z9wNGLKQ0kSFyjN38gMqU1SfP+TUNQepFHb/Gc0E2 CxXPkIBTvYY+ZPkoTh5xF9oS1jqI8iRLzouzF8yXs3QjQIZ2SfuCxSVwlV65jotcjD2FTN04 hVopm9llFijNZpVIOGUTqzM4U55sdsCcZUluWM6x4HSOdw5F5Utxfp1wOjD/v92Lrax0hjiX DResHSt48q+8FrZzY+AUbkUS+Jm34qjswdrgsC5uxeVcLkBgWLmov2kMaMROT0YmFY6A3m1S P/kXmHDXxhe23gKb3dgwxUTpENDBGcfEzrzilWueOeUWiOcWuFOed/C3SyijBx3Av/lbCsHU Vx6pMycNTdzU1BuAroB+Y3mNEuW56Yd44jlInzG2UOwt9XjjdKkJZ1g0P9dwptwLEgTEd3Fo UdhAQyRXGYO8oROiuh+RZ1lXp6AQ4ZjoyH8WLfTLf5g1EKCTc4C1sy1vQSdzIRu3rBIjAvnC tGZADei1IExLqB3uzXKzZ1BZ+Z8hnt2og9hb7H0y8diYfEk2w3R7wEr+Ehk5NQsT2MPI2QBd wEv1/Aj1DgUHZAHzG1QN9S8wNWQ6K9DqHZTBnI1hUlkp22zCSHK/6FwUCuYp1zcAEQEAAc0j UGFvbG8gQm9uemluaSA8cGJvbnppbmlAcmVkaGF0LmNvbT7CwU0EEwECACMFAlRCcBICGwMH CwkIBwMCAQYVCAIJCgsEFgIDAQIeAQIXgAAKCRB+FRAMzTZpsbceDp9IIN6BIA0Ol7MoB15E 11kRz/ewzryFY54tQlMnd4xxfH8MTQ/mm9I482YoSwPMdcWFAKnUX6Yo30tbLiNB8hzaHeRj jx12K+ptqYbg+cevgOtbLAlL9kNgLLcsGqC2829jBCUTVeMSZDrzS97ole/YEez2qFpPnTV0 VrRWClWVfYh+JfzpXmgyhbkuwUxNFk421s4Ajp3d8nPPFUGgBG5HOxzkAm7xb1cjAuJ+oi/K CHfkuN+fLZl/u3E/fw7vvOESApLU5o0icVXeakfSz0LsygEnekDbxPnE5af/9FEkXJD5EoYG SEahaEtgNrR4qsyxyAGYgZlS70vkSSYJ+iT2rrwEiDlo31MzRo6Ba2FfHBSJ7lcYdPT7bbk9 AO3hlNMhNdUhoQv7M5HsnqZ6unvSHOKmReNaS9egAGdRN0/GPDWr9wroyJ65ZNQsHl9nXBqE AukZNr5oJO5vxrYiAuuTSd6UI/xFkjtkzltG3mw5ao2bBpk/V/YuePrJsnPFHG7NhizrxttB nTuOSCMo45pfHQ+XYd5K1+Cv/NzZFNWscm5htJ0HznY+oOsZvHTyGz3v91pn51dkRYN0otqr bQ4tlFFuVjArBZcapSIe6NV8C4cEiSTOwE0EVEJx7gEIAMeHcVzuv2bp9HlWDp6+RkZe+vtl KwAHplb/WH59j2wyG8V6i33+6MlSSJMOFnYUCCL77bucx9uImI5nX24PIlqT+zasVEEVGSRF m8dgkcJDB7Tps0IkNrUi4yof3B3shR+vMY3i3Ip0e41zKx0CvlAhMOo6otaHmcxr35sWq1Jk tLkbn3wG+fPQCVudJJECvVQ//UAthSSEklA50QtD2sBkmQ14ZryEyTHQ+E42K3j2IUmOLriF dNr9NvE1QGmGyIcbw2NIVEBOK/GWxkS5+dmxM2iD4Jdaf2nSn3jlHjEXoPwpMs0KZsgdU0pP JQzMUMwmB1wM8JxovFlPYrhNT9MAEQEAAcLBMwQYAQIACQUCVEJx7gIbDAAKCRB+FRAMzTZp sadRDqCctLmYICZu4GSnie4lKXl+HqlLanpVMOoFNnWs9oRP47MbE2wv8OaYh5pNR9VVgyhD OG0AU7oidG36OeUlrFDTfnPYYSF/mPCxHttosyt8O5kabxnIPv2URuAxDByz+iVbL+RjKaGM GDph56ZTswlx75nZVtIukqzLAQ5fa8OALSGum0cFi4ptZUOhDNz1onz61klD6z3MODi0sBZN Aj6guB2L/+2ZwElZEeRBERRd/uommlYuToAXfNRdUwrwl9gRMiA0WSyTb190zneRRDfpSK5d usXnM/O+kr3Dm+Ui+UioPf6wgbn3T0o6I5BhVhs4h4hWmIW7iNhPjX1iybXfmb1gAFfjtHfL xRUr64svXpyfJMScIQtBAm0ihWPltXkyITA92ngCmPdHa6M1hMh4RDX+Jf1fiWubzp1voAg0 JBrdmNZSQDz0iKmSrx8xkoXYfA3bgtFN8WJH2xgFL28XnqY4M6dLhJwV3z08tPSRqYFm4NMP dRsn0/7oymhneL8RthIvjDDQ5ktUjMe8LtHr70OZE/TT88qvEdhiIVUogHdo4qBrk41+gGQh b906Dudw5YhTJFU3nC6bbF2nrLlB4C/XSiH76ZvqzV0Z/cAMBo5NF/w= In-Reply-To: <20260512011502.53072-7-chang.seok.bae@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 On 5/12/26 03:14, Chang S. Bae wrote: > From: Paolo Bonzini > > KVM will store APX extended GPRs directly in the regs[] field of struct > kvm_vcpu. This is done to make accessors more uniform between GPRs and > EGPRs, and partly because x86 maintainers expressed the desire to compile > Linux with APX enabled sooner or later; accessing guest EGPRs from KVM's > C code would get in the way. > > Therefore, let KVM handle the APX feature on its own when executing > ioctls to get and set the virtual machine's XSAVE state. > > Cc: x86@kernel.org > Signed-off-by: Paolo Bonzini > [ chang: adjust function prototype ] > Signed-off-by: Chang S. Bae Boris, Dave, can you please ACK these changes to core FPU code? Thanks, Paolo > --- > V3 -> V4: New patch > --- > arch/x86/include/asm/fpu/api.h | 2 +- > arch/x86/kernel/fpu/core.c | 9 +++++++-- > 2 files changed, 8 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h > index cd6f194a912b..0b218f5eaafd 100644 > --- a/arch/x86/include/asm/fpu/api.h > +++ b/arch/x86/include/asm/fpu/api.h > @@ -160,7 +160,7 @@ static inline void fpu_sync_guest_vmexit_xfd_state(void) { } > > extern void fpu_copy_guest_fpstate_to_uabi(struct fpu_guest *gfpu, void *buf, > unsigned int size, u64 xfeatures, u32 pkru); > -extern int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf, u64 xcr0, u32 *vpkru); > +extern int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, void *buf, u64 xcr0, u32 *vpkru); > > static inline void fpstate_set_confidential(struct fpu_guest *gfpu) > { > diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c > index 608983806fd7..ae5c73faed69 100644 > --- a/arch/x86/kernel/fpu/core.c > +++ b/arch/x86/kernel/fpu/core.c > @@ -420,6 +420,8 @@ void fpu_copy_guest_fpstate_to_uabi(struct fpu_guest *gfpu, void *buf, > struct membuf mb = { .p = buf, .left = size }; > > if (cpu_feature_enabled(X86_FEATURE_XSAVE)) { > + /* Up to date APX registers are in struct kvm_vcpu anyway. */ > + xfeatures &= ~XFEATURE_MASK_APX; > __copy_xstate_to_uabi_buf(mb, kstate, xfeatures, pkru, > XSTATE_COPY_XSAVE); > } else { > @@ -431,11 +433,11 @@ void fpu_copy_guest_fpstate_to_uabi(struct fpu_guest *gfpu, void *buf, > } > EXPORT_SYMBOL_FOR_KVM(fpu_copy_guest_fpstate_to_uabi); > > -int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf, > +int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, void *buf, > u64 xcr0, u32 *vpkru) > { > struct fpstate *kstate = gfpu->fpstate; > - const union fpregs_state *ustate = buf; > + union fpregs_state *ustate = buf; > > if (!cpu_feature_enabled(X86_FEATURE_XSAVE)) { > if (ustate->xsave.header.xfeatures & ~XFEATURE_MASK_FPSSE) > @@ -464,6 +466,9 @@ int fpu_copy_uabi_to_guest_fpstate(struct fpu_guest *gfpu, const void *buf, > if (!(ustate->xsave.header.xfeatures & XFEATURE_MASK_PKRU)) > vpkru = NULL; > > + /* APX registers are copied to and from struct kvm_vcpu, not the FPU. */ > + ustate->xsave.header.xfeatures &= ~XFEATURE_MASK_APX; > + > return copy_uabi_from_kernel_to_xstate(kstate, ustate, vpkru); > } > EXPORT_SYMBOL_FOR_KVM(fpu_copy_uabi_to_guest_fpstate);