From: Dexuan Cui <decui@xxxxxxxxxxxxx> Sent: Monday, November 21, 2022 11:52 AM > > A TDX guest uses the GHCI call rather than hv_hypercall_pg. > > In hv_do_hypercall(), Hyper-V requires that the input/output addresses > must have the vTOM bit set. With current Hyper-V, the bit for TDX is > bit 47, which is saved into ms_hyperv.shared_gpa_boundary() in > ms_hyperv_init_platform(). > > arch/x86/include/asm/mshyperv.h: hv_do_hypercall() needs > "struct ms_hyperv_info", which is defined in > include/asm-generic/mshyperv.h, which can't be included in > arch/x86/include/asm/mshyperv.h because include/asm-generic/mshyperv.h > has vmbus_signal_eom() -> hv_set_register(), which is defined in > arch/x86/include/asm/mshyperv.h. > > Break this circular dependency by introducing a new header file > for "struct ms_hyperv_info". > > Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx> > --- > MAINTAINERS | 1 + > arch/x86/hyperv/hv_init.c | 8 ++++++++ > arch/x86/include/asm/mshyperv.h | 24 ++++++++++++++++++++++- > arch/x86/kernel/cpu/mshyperv.c | 2 ++ > include/asm-generic/ms_hyperv_info.h | 29 ++++++++++++++++++++++++++++ > include/asm-generic/mshyperv.h | 24 +---------------------- > 6 files changed, 64 insertions(+), 24 deletions(-) > create mode 100644 include/asm-generic/ms_hyperv_info.h > > diff --git a/MAINTAINERS b/MAINTAINERS > index 256f03904987..455ecaf188fe 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -9537,6 +9537,7 @@ F: drivers/scsi/storvsc_drv.c > F: drivers/uio/uio_hv_generic.c > F: drivers/video/fbdev/hyperv_fb.c > F: include/asm-generic/hyperv-tlfs.h > +F: include/asm-generic/ms_hyperv_info.h > F: include/asm-generic/mshyperv.h > F: include/clocksource/hyperv_timer.h > F: include/linux/hyperv.h > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c > index 89954490af93..05682c4e327f 100644 > --- a/arch/x86/hyperv/hv_init.c > +++ b/arch/x86/hyperv/hv_init.c > @@ -432,6 +432,10 @@ void __init hyperv_init(void) > /* Hyper-V requires to write guest os id via ghcb in SNP IVM. */ > hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id); > > + /* A TDX guest uses the GHCI call rather than hv_hypercall_pg. */ > + if (hv_isolation_type_tdx()) > + goto skip_hypercall_pg_init; > + > hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, > VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX, > VM_FLUSH_RESET_PERMS, NUMA_NO_NODE, > @@ -471,6 +475,7 @@ void __init hyperv_init(void) > wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); > } > > +skip_hypercall_pg_init: > /* > * hyperv_init() is called before LAPIC is initialized: see > * apic_intr_mode_init() -> x86_platform.apic_post_init() and > @@ -606,6 +611,9 @@ bool hv_is_hyperv_initialized(void) > if (x86_hyper_type != X86_HYPER_MS_HYPERV) > return false; > > + /* A TDX guest uses the GHCI call rather than hv_hypercall_pg. */ > + if (hv_isolation_type_tdx()) > + return true; > /* > * Verify that earlier initialization succeeded by checking > * that the hypercall page is setup > diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h > index 9d593ab2be26..650b4fae2fd8 100644 > --- a/arch/x86/include/asm/mshyperv.h > +++ b/arch/x86/include/asm/mshyperv.h > @@ -9,7 +9,7 @@ > #include <asm/hyperv-tlfs.h> > #include <asm/nospec-branch.h> > #include <asm/paravirt.h> > -#include <asm/mshyperv.h> > +#include <asm-generic/ms_hyperv_info.h> > > union hv_ghcb; > > @@ -48,6 +48,18 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void > *output) > u64 hv_status; > > #ifdef CONFIG_X86_64 > +#if CONFIG_INTEL_TDX_GUEST > + if (hv_isolation_type_tdx()) { > + if (input_address) > + input_address += ms_hyperv.shared_gpa_boundary; > + > + if (output_address) > + output_address += ms_hyperv.shared_gpa_boundary; > + > + return __tdx_ms_hv_hypercall(control, output_address, > + input_address); > + } > +#endif Two thoughts: 1) The #ifdef CONFIG_INTEL_TDX_GUEST could probably be removed entirely with a tweak. hv_isolation_type_tdx() already doesn't need the #ifdef as there's already a stub that returns 'false'. Then you just need a way to handle __tdx_ms_hv_hypercall(), or whatever it becomes based on the other discussion. As long as you can provide a stub that does nothing, the #ifdef won't be needed. 2) Assuming that we end up with some kind of Hyper-V specific version of __tdx_hypercall(), and hopefully as a "C" function, could you move the handling of ms_hyperv.shared_gpa_boundary into that function? Then you won't need to break out a separate include file for struct ms_hyperv. The Hyper-V TDX hypercall function must handle both normal and "fast" hypercalls, and the shared_gpa_boundary adjustment is needed only for normal hypercalls, but you can check the "fast" bit in the control word to decide. I haven't coded these ideas, so maybe there are snags I haven't thought of. But I'm really hoping we can avoid having to create a separate include file for struct ms_hyperv. Michael > if (!hv_hypercall_pg) > return U64_MAX; > > @@ -85,6 +97,11 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1) > u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT; > > #ifdef CONFIG_X86_64 > +#if CONFIG_INTEL_TDX_GUEST > + if (hv_isolation_type_tdx()) > + return __tdx_ms_hv_hypercall(control, 0, input1); > +#endif > + > { > __asm__ __volatile__(CALL_NOSPEC > : "=a" (hv_status), ASM_CALL_CONSTRAINT, > @@ -116,6 +133,11 @@ static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, > u64 input2) > u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT; > > #ifdef CONFIG_X86_64 > +#if CONFIG_INTEL_TDX_GUEST > + if (hv_isolation_type_tdx()) > + return __tdx_ms_hv_hypercall(control, input2, input1); > +#endif > + > { > __asm__ __volatile__("mov %4, %%r8\n" > CALL_NOSPEC > diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c > index 9ad0b0abf0e0..dddccdbc5526 100644 > --- a/arch/x86/kernel/cpu/mshyperv.c > +++ b/arch/x86/kernel/cpu/mshyperv.c > @@ -349,6 +349,8 @@ static void __init ms_hyperv_init_platform(void) > > case HV_ISOLATION_TYPE_TDX: > static_branch_enable(&isolation_type_tdx); > + > + ms_hyperv.shared_gpa_boundary = cc_mkdec(0); > break; > > default: > diff --git a/include/asm-generic/ms_hyperv_info.h b/include/asm- > generic/ms_hyperv_info.h > new file mode 100644 > index 000000000000..734583dfea99 > --- /dev/null > +++ b/include/asm-generic/ms_hyperv_info.h > @@ -0,0 +1,29 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > + > +#ifndef _ASM_GENERIC_MS_HYPERV_INFO_H > +#define _ASM_GENERIC_MS_HYPERV_INFO_H > + > +struct ms_hyperv_info { > + u32 features; > + u32 priv_high; > + u32 misc_features; > + u32 hints; > + u32 nested_features; > + u32 max_vp_index; > + u32 max_lp_index; > + u32 isolation_config_a; > + union { > + u32 isolation_config_b; > + struct { > + u32 cvm_type : 4; > + u32 reserved1 : 1; > + u32 shared_gpa_boundary_active : 1; > + u32 shared_gpa_boundary_bits : 6; > + u32 reserved2 : 20; > + }; > + }; > + u64 shared_gpa_boundary; > +}; > +extern struct ms_hyperv_info ms_hyperv; > + > +#endif > diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h > index bfb9eb9d7215..2ae3e4e4256b 100644 > --- a/include/asm-generic/mshyperv.h > +++ b/include/asm-generic/mshyperv.h > @@ -25,29 +25,7 @@ > #include <linux/nmi.h> > #include <asm/ptrace.h> > #include <asm/hyperv-tlfs.h> > - > -struct ms_hyperv_info { > - u32 features; > - u32 priv_high; > - u32 misc_features; > - u32 hints; > - u32 nested_features; > - u32 max_vp_index; > - u32 max_lp_index; > - u32 isolation_config_a; > - union { > - u32 isolation_config_b; > - struct { > - u32 cvm_type : 4; > - u32 reserved1 : 1; > - u32 shared_gpa_boundary_active : 1; > - u32 shared_gpa_boundary_bits : 6; > - u32 reserved2 : 20; > - }; > - }; > - u64 shared_gpa_boundary; > -}; > -extern struct ms_hyperv_info ms_hyperv; > +#include <asm-generic/ms_hyperv_info.h> > > extern void * __percpu *hyperv_pcpu_input_arg; > extern void * __percpu *hyperv_pcpu_output_arg; > -- > 2.25.1