| Message ID | f3293bd872a916bf33165a2ec0d6fc50533b817f.1646422845.git.isaku.yamahata@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM TDX basic feature support | expand |
On Fri, Mar 4, 2022 at 12:00 PM <isaku.yamahata@intel.com> wrote: > > From: Sean Christopherson <sean.j.christopherson@intel.com> > > By necessity, TDX will use a different register ABI for hypercalls. > Break out the core functionality so that it may be reused for TDX. > > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > --- > arch/x86/include/asm/kvm_host.h | 4 +++ > arch/x86/kvm/x86.c | 54 ++++++++++++++++++++------------- > 2 files changed, 37 insertions(+), 21 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 8dab9f16f559..33b75b0e3de1 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -1818,6 +1818,10 @@ void kvm_request_apicv_update(struct kvm *kvm, bool activate, > void __kvm_request_apicv_update(struct kvm *kvm, bool activate, > unsigned long bit); > > +unsigned long __kvm_emulate_hypercall(struct kvm_vcpu *vcpu, unsigned long nr, > + unsigned long a0, unsigned long a1, > + unsigned long a2, unsigned long a3, > + int op_64_bit); > int kvm_emulate_hypercall(struct kvm_vcpu *vcpu); > > int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code, > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 314ae43e07bf..9acb33a17445 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -9090,26 +9090,15 @@ static int complete_hypercall_exit(struct kvm_vcpu *vcpu) > return kvm_skip_emulated_instruction(vcpu); > } > > -int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) > +unsigned long __kvm_emulate_hypercall(struct kvm_vcpu *vcpu, unsigned long nr, > + unsigned long a0, unsigned long a1, > + unsigned long a2, unsigned long a3, > + int op_64_bit) > { > - unsigned long nr, a0, a1, a2, a3, ret; > - int op_64_bit; > - > - if (kvm_xen_hypercall_enabled(vcpu->kvm)) > - return kvm_xen_hypercall(vcpu); > - > - if (kvm_hv_hypercall_enabled(vcpu)) > - return kvm_hv_hypercall(vcpu); > - > - nr = kvm_rax_read(vcpu); > - a0 = kvm_rbx_read(vcpu); > - a1 = kvm_rcx_read(vcpu); > - a2 = kvm_rdx_read(vcpu); > - a3 = kvm_rsi_read(vcpu); > + unsigned long ret; > > trace_kvm_hypercall(nr, a0, a1, a2, a3); > > - op_64_bit = is_64_bit_hypercall(vcpu); > if (!op_64_bit) { > nr &= 0xFFFFFFFF; > a0 &= 0xFFFFFFFF; > @@ -9118,11 +9107,6 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) > a3 &= 0xFFFFFFFF; > } > > - if (static_call(kvm_x86_get_cpl)(vcpu) != 0) { > - ret = -KVM_EPERM; > - goto out; > - } > - > ret = -KVM_ENOSYS; > > switch (nr) { > @@ -9181,6 +9165,34 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) > ret = -KVM_ENOSYS; > break; > } > + return ret; > +} > +EXPORT_SYMBOL_GPL(__kvm_emulate_hypercall); > + > +int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) > +{ > + unsigned long nr, a0, a1, a2, a3, ret; > + int op_64_bit; > + > + if (kvm_xen_hypercall_enabled(vcpu->kvm)) > + return kvm_xen_hypercall(vcpu); > + > + if (kvm_hv_hypercall_enabled(vcpu)) > + return kvm_hv_hypercall(vcpu); > + > + nr = kvm_rax_read(vcpu); > + a0 = kvm_rbx_read(vcpu); > + a1 = kvm_rcx_read(vcpu); > + a2 = kvm_rdx_read(vcpu); > + a3 = kvm_rsi_read(vcpu); > + op_64_bit = is_64_bit_mode(vcpu); I think this should be "op_64_bit = is_64_bit_hypercall(vcpu);" is_64_bit_mode was replaced with is_64_bit_hypercall to support protected guests here: https://lore.kernel.org/all/87cztf8h43.fsf@vitty.brq.redhat.com/T/ Without it, op_64_bit will be set to 0 for TD VMs which will cause the upper 32 bit of the registers to be cleared in __kvm_emulate_hypercall > + > + if (static_call(kvm_x86_get_cpl)(vcpu) != 0) { > + ret = -KVM_EPERM; > + goto out; > + } > + > + ret = __kvm_emulate_hypercall(vcpu, nr, a0, a1, a2, a3, op_64_bit); > out: > if (!op_64_bit) > ret = (u32)ret; > -- > 2.25.1 > Sagi
On Mon, Mar 21, 2022 at 11:32:21AM -0700, Sagi Shahar <sagis@google.com> wrote: > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index 314ae43e07bf..9acb33a17445 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -9090,26 +9090,15 @@ static int complete_hypercall_exit(struct kvm_vcpu *vcpu) > > return kvm_skip_emulated_instruction(vcpu); > > } > > > > -int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) > > +unsigned long __kvm_emulate_hypercall(struct kvm_vcpu *vcpu, unsigned long nr, > > + unsigned long a0, unsigned long a1, > > + unsigned long a2, unsigned long a3, > > + int op_64_bit) > > { > > - unsigned long nr, a0, a1, a2, a3, ret; > > - int op_64_bit; > > - > > - if (kvm_xen_hypercall_enabled(vcpu->kvm)) > > - return kvm_xen_hypercall(vcpu); > > - > > - if (kvm_hv_hypercall_enabled(vcpu)) > > - return kvm_hv_hypercall(vcpu); > > - > > - nr = kvm_rax_read(vcpu); > > - a0 = kvm_rbx_read(vcpu); > > - a1 = kvm_rcx_read(vcpu); > > - a2 = kvm_rdx_read(vcpu); > > - a3 = kvm_rsi_read(vcpu); > > + unsigned long ret; > > > > trace_kvm_hypercall(nr, a0, a1, a2, a3); > > > > - op_64_bit = is_64_bit_hypercall(vcpu); > > if (!op_64_bit) { > > nr &= 0xFFFFFFFF; > > a0 &= 0xFFFFFFFF; > > @@ -9118,11 +9107,6 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) > > a3 &= 0xFFFFFFFF; > > } > > > > - if (static_call(kvm_x86_get_cpl)(vcpu) != 0) { > > - ret = -KVM_EPERM; > > - goto out; > > - } > > - > > ret = -KVM_ENOSYS; > > > > switch (nr) { > > @@ -9181,6 +9165,34 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) > > ret = -KVM_ENOSYS; > > break; > > } > > + return ret; > > +} > > +EXPORT_SYMBOL_GPL(__kvm_emulate_hypercall); > > + > > +int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) > > +{ > > + unsigned long nr, a0, a1, a2, a3, ret; > > + int op_64_bit; > > + > > + if (kvm_xen_hypercall_enabled(vcpu->kvm)) > > + return kvm_xen_hypercall(vcpu); > > + > > + if (kvm_hv_hypercall_enabled(vcpu)) > > + return kvm_hv_hypercall(vcpu); > > + > > + nr = kvm_rax_read(vcpu); > > + a0 = kvm_rbx_read(vcpu); > > + a1 = kvm_rcx_read(vcpu); > > + a2 = kvm_rdx_read(vcpu); > > + a3 = kvm_rsi_read(vcpu); > > + op_64_bit = is_64_bit_mode(vcpu); > > I think this should be "op_64_bit = is_64_bit_hypercall(vcpu);" > is_64_bit_mode was replaced with is_64_bit_hypercall to support > protected guests here: > https://lore.kernel.org/all/87cztf8h43.fsf@vitty.brq.redhat.com/T/ > > Without it, op_64_bit will be set to 0 for TD VMs which will cause the > upper 32 bit of the registers to be cleared in __kvm_emulate_hypercall Oops, thanks for pointing it out. I'll fix it up with next respin.
On 3/21/22 19:32, Sagi Shahar wrote: > On Fri, Mar 4, 2022 at 12:00 PM <isaku.yamahata@intel.com> wrote: >> >> From: Sean Christopherson <sean.j.christopherson@intel.com> >> >> By necessity, TDX will use a different register ABI for hypercalls. >> Break out the core functionality so that it may be reused for TDX. >> >> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> >> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> >> --- >> arch/x86/include/asm/kvm_host.h | 4 +++ >> arch/x86/kvm/x86.c | 54 ++++++++++++++++++++------------- >> 2 files changed, 37 insertions(+), 21 deletions(-) >> >> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h >> index 8dab9f16f559..33b75b0e3de1 100644 >> --- a/arch/x86/include/asm/kvm_host.h >> +++ b/arch/x86/include/asm/kvm_host.h >> @@ -1818,6 +1818,10 @@ void kvm_request_apicv_update(struct kvm *kvm, bool activate, >> void __kvm_request_apicv_update(struct kvm *kvm, bool activate, >> unsigned long bit); >> >> +unsigned long __kvm_emulate_hypercall(struct kvm_vcpu *vcpu, unsigned long nr, >> + unsigned long a0, unsigned long a1, >> + unsigned long a2, unsigned long a3, >> + int op_64_bit); >> int kvm_emulate_hypercall(struct kvm_vcpu *vcpu); >> >> int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code, >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index 314ae43e07bf..9acb33a17445 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -9090,26 +9090,15 @@ static int complete_hypercall_exit(struct kvm_vcpu *vcpu) >> return kvm_skip_emulated_instruction(vcpu); >> } >> >> -int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) >> +unsigned long __kvm_emulate_hypercall(struct kvm_vcpu *vcpu, unsigned long nr, >> + unsigned long a0, unsigned long a1, >> + unsigned long a2, unsigned long a3, >> + int op_64_bit) >> { >> - unsigned long nr, a0, a1, a2, a3, ret; >> - int op_64_bit; >> - >> - if (kvm_xen_hypercall_enabled(vcpu->kvm)) >> - return kvm_xen_hypercall(vcpu); >> - >> - if (kvm_hv_hypercall_enabled(vcpu)) >> - return kvm_hv_hypercall(vcpu); Please keep Xen and Hyper-V hypercalls to kvm_emulate_hypercall (more on this in the reply to patch 89). __kvm_emulate_hypercall should only handle KVM hypercalls. >> + if (static_call(kvm_x86_get_cpl)(vcpu) != 0) { >> + ret = -KVM_EPERM; >> + goto out; >> + } Is this guaranteed by TDG.VP.VMCALL? Paolo >> + ret = __kvm_emulate_hypercall(vcpu, nr, a0, a1, a2, a3, op_64_bit); >> out: >> if (!op_64_bit) >> ret = (u32)ret; >> -- >> 2.25.1 >> > > Sagi >
On Thu, Apr 07, 2022 at 03:12:57PM +0200, Paolo Bonzini <pbonzini@redhat.com> wrote: > > > + if (static_call(kvm_x86_get_cpl)(vcpu) != 0) { > > > + ret = -KVM_EPERM; > > > + goto out; > > > + } > > Is this guaranteed by TDG.VP.VMCALL? Yes. TDCALL instruction in TD results in #GP(0) if CPL > 0. It's documented in trust domain CPU architectural extensions spec. https://www.intel.com/content/dam/develop/external/us/en/documents-tps/intel-tdx-cpu-architectural-specification.pdf Anyway VMM can't know TD guest CPL (or other CPU state).
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 8dab9f16f559..33b75b0e3de1 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1818,6 +1818,10 @@ void kvm_request_apicv_update(struct kvm *kvm, bool activate, void __kvm_request_apicv_update(struct kvm *kvm, bool activate, unsigned long bit); +unsigned long __kvm_emulate_hypercall(struct kvm_vcpu *vcpu, unsigned long nr, + unsigned long a0, unsigned long a1, + unsigned long a2, unsigned long a3, + int op_64_bit); int kvm_emulate_hypercall(struct kvm_vcpu *vcpu); int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 314ae43e07bf..9acb33a17445 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9090,26 +9090,15 @@ static int complete_hypercall_exit(struct kvm_vcpu *vcpu) return kvm_skip_emulated_instruction(vcpu); } -int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) +unsigned long __kvm_emulate_hypercall(struct kvm_vcpu *vcpu, unsigned long nr, + unsigned long a0, unsigned long a1, + unsigned long a2, unsigned long a3, + int op_64_bit) { - unsigned long nr, a0, a1, a2, a3, ret; - int op_64_bit; - - if (kvm_xen_hypercall_enabled(vcpu->kvm)) - return kvm_xen_hypercall(vcpu); - - if (kvm_hv_hypercall_enabled(vcpu)) - return kvm_hv_hypercall(vcpu); - - nr = kvm_rax_read(vcpu); - a0 = kvm_rbx_read(vcpu); - a1 = kvm_rcx_read(vcpu); - a2 = kvm_rdx_read(vcpu); - a3 = kvm_rsi_read(vcpu); + unsigned long ret; trace_kvm_hypercall(nr, a0, a1, a2, a3); - op_64_bit = is_64_bit_hypercall(vcpu); if (!op_64_bit) { nr &= 0xFFFFFFFF; a0 &= 0xFFFFFFFF; @@ -9118,11 +9107,6 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) a3 &= 0xFFFFFFFF; } - if (static_call(kvm_x86_get_cpl)(vcpu) != 0) { - ret = -KVM_EPERM; - goto out; - } - ret = -KVM_ENOSYS; switch (nr) { @@ -9181,6 +9165,34 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) ret = -KVM_ENOSYS; break; } + return ret; +} +EXPORT_SYMBOL_GPL(__kvm_emulate_hypercall); + +int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) +{ + unsigned long nr, a0, a1, a2, a3, ret; + int op_64_bit; + + if (kvm_xen_hypercall_enabled(vcpu->kvm)) + return kvm_xen_hypercall(vcpu); + + if (kvm_hv_hypercall_enabled(vcpu)) + return kvm_hv_hypercall(vcpu); + + nr = kvm_rax_read(vcpu); + a0 = kvm_rbx_read(vcpu); + a1 = kvm_rcx_read(vcpu); + a2 = kvm_rdx_read(vcpu); + a3 = kvm_rsi_read(vcpu); + op_64_bit = is_64_bit_mode(vcpu); + + if (static_call(kvm_x86_get_cpl)(vcpu) != 0) { + ret = -KVM_EPERM; + goto out; + } + + ret = __kvm_emulate_hypercall(vcpu, nr, a0, a1, a2, a3, op_64_bit); out: if (!op_64_bit) ret = (u32)ret;