| Message ID | 1eb584469b41775380ab0a5a5d31a64e344b1b95.1625186503.git.isaku.yamahata@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: X86: TDX support | expand |
On 03/07/21 00:04, isaku.yamahata@intel.com wrote: > From: Isaku Yamahata <isaku.yamahata@intel.com> > > Add a flag for TDX to flag RO memory as unsupported and propagate it to > KVM_MEM_READONLY to allow reporting RO memory as unsupported on a per-VM > basis. TDX1 doesn't expose permission bits to the VMM in the SEPT > tables, i.e. doesn't support read-only private memory. > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com> > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > --- > arch/x86/kvm/x86.c | 4 +++- > include/linux/kvm_host.h | 4 ++++ > virt/kvm/kvm_main.c | 8 +++++--- > 3 files changed, 12 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index cd9407982366..87212d7563ae 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -3897,7 +3897,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > case KVM_CAP_ASYNC_PF_INT: > case KVM_CAP_GET_TSC_KHZ: > case KVM_CAP_KVMCLOCK_CTRL: > - case KVM_CAP_READONLY_MEM: > case KVM_CAP_HYPERV_TIME: > case KVM_CAP_IOAPIC_POLARITY_IGNORED: > case KVM_CAP_TSC_DEADLINE_TIMER: > @@ -4009,6 +4008,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) > if (static_call(kvm_x86_is_vm_type_supported)(KVM_X86_TDX_VM)) > r |= BIT(KVM_X86_TDX_VM); > break; > + case KVM_CAP_READONLY_MEM: > + r = kvm && kvm->readonly_mem_unsupported ? 0 : 1; > + break; > default: > break; > } > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index ddd4d0f68cdf..7ee7104b4b59 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -597,6 +597,10 @@ struct kvm { > unsigned int max_halt_poll_ns; > u32 dirty_ring_size; > > +#ifdef __KVM_HAVE_READONLY_MEM > + bool readonly_mem_unsupported; > +#endif > + > bool vm_bugged; > }; > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 52d40ea75749..63d0c2833913 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -1258,12 +1258,14 @@ static void update_memslots(struct kvm_memslots *slots, > } > } > > -static int check_memory_region_flags(const struct kvm_userspace_memory_region *mem) > +static int check_memory_region_flags(struct kvm *kvm, > + const struct kvm_userspace_memory_region *mem) > { > u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; > > #ifdef __KVM_HAVE_READONLY_MEM > - valid_flags |= KVM_MEM_READONLY; > + if (!kvm->readonly_mem_unsupported) > + valid_flags |= KVM_MEM_READONLY; > #endif > > if (mem->flags & ~valid_flags) > @@ -1436,7 +1438,7 @@ int __kvm_set_memory_region(struct kvm *kvm, > int as_id, id; > int r; > > - r = check_memory_region_flags(mem); > + r = check_memory_region_flags(kvm, mem); > if (r) > return r; > > For all these flags, which of these limitations will be common to SEV-ES and SEV-SNP (ExtINT injection, MCE injection, changing TSC, read-only memory, dirty logging)? Would it make sense to use vm_type instead of all of them? I guess this also guides the choice of whether to use a single vm-type for TDX and SEV-SNP or two. Probably two is better, and there can be static inline bool functions to derive the support flags from the vm-type. Paolo
On 7/6/21 9:03 AM, Paolo Bonzini wrote: > On 03/07/21 00:04, isaku.yamahata@intel.com wrote: >> From: Isaku Yamahata <isaku.yamahata@intel.com> >> >> Add a flag for TDX to flag RO memory as unsupported and propagate it to >> KVM_MEM_READONLY to allow reporting RO memory as unsupported on a per-VM >> basis. TDX1 doesn't expose permission bits to the VMM in the SEPT >> tables, i.e. doesn't support read-only private memory. >> >> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> >> Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com> >> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> >> --- >> arch/x86/kvm/x86.c | 4 +++- >> include/linux/kvm_host.h | 4 ++++ >> virt/kvm/kvm_main.c | 8 +++++--- >> 3 files changed, 12 insertions(+), 4 deletions(-) >> >> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> index cd9407982366..87212d7563ae 100644 >> --- a/arch/x86/kvm/x86.c >> +++ b/arch/x86/kvm/x86.c >> @@ -3897,7 +3897,6 @@ int kvm_vm_ioctl_check_extension(struct kvm >> *kvm, long ext) >> case KVM_CAP_ASYNC_PF_INT: >> case KVM_CAP_GET_TSC_KHZ: >> case KVM_CAP_KVMCLOCK_CTRL: >> - case KVM_CAP_READONLY_MEM: >> case KVM_CAP_HYPERV_TIME: >> case KVM_CAP_IOAPIC_POLARITY_IGNORED: >> case KVM_CAP_TSC_DEADLINE_TIMER: >> @@ -4009,6 +4008,9 @@ int kvm_vm_ioctl_check_extension(struct kvm >> *kvm, long ext) >> if (static_call(kvm_x86_is_vm_type_supported)(KVM_X86_TDX_VM)) >> r |= BIT(KVM_X86_TDX_VM); >> break; >> + case KVM_CAP_READONLY_MEM: >> + r = kvm && kvm->readonly_mem_unsupported ? 0 : 1; >> + break; >> default: >> break; >> } >> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h >> index ddd4d0f68cdf..7ee7104b4b59 100644 >> --- a/include/linux/kvm_host.h >> +++ b/include/linux/kvm_host.h >> @@ -597,6 +597,10 @@ struct kvm { >> unsigned int max_halt_poll_ns; >> u32 dirty_ring_size; >> +#ifdef __KVM_HAVE_READONLY_MEM >> + bool readonly_mem_unsupported; >> +#endif >> + >> bool vm_bugged; >> }; >> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c >> index 52d40ea75749..63d0c2833913 100644 >> --- a/virt/kvm/kvm_main.c >> +++ b/virt/kvm/kvm_main.c >> @@ -1258,12 +1258,14 @@ static void update_memslots(struct >> kvm_memslots *slots, >> } >> } >> -static int check_memory_region_flags(const struct >> kvm_userspace_memory_region *mem) >> +static int check_memory_region_flags(struct kvm *kvm, >> + const struct kvm_userspace_memory_region *mem) >> { >> u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; >> #ifdef __KVM_HAVE_READONLY_MEM >> - valid_flags |= KVM_MEM_READONLY; >> + if (!kvm->readonly_mem_unsupported) >> + valid_flags |= KVM_MEM_READONLY; >> #endif >> if (mem->flags & ~valid_flags) >> @@ -1436,7 +1438,7 @@ int __kvm_set_memory_region(struct kvm *kvm, >> int as_id, id; >> int r; >> - r = check_memory_region_flags(mem); >> + r = check_memory_region_flags(kvm, mem); >> if (r) >> return r; >> > > For all these flags, which of these limitations will be common to SEV-ES > and SEV-SNP (ExtINT injection, MCE injection, changing TSC, read-only > memory, dirty logging)? Would it make sense to use vm_type instead of > all of them? I guess this also guides the choice of whether to use a > single vm-type for TDX and SEV-SNP or two. Probably two is better, and > there can be static inline bool functions to derive the support flags > from the vm-type. > The SEV-ES does not need any of these flags. However, with SEV-SNP, we may able use the ExtINT injection. -Brijesh
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index cd9407982366..87212d7563ae 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3897,7 +3897,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_ASYNC_PF_INT: case KVM_CAP_GET_TSC_KHZ: case KVM_CAP_KVMCLOCK_CTRL: - case KVM_CAP_READONLY_MEM: case KVM_CAP_HYPERV_TIME: case KVM_CAP_IOAPIC_POLARITY_IGNORED: case KVM_CAP_TSC_DEADLINE_TIMER: @@ -4009,6 +4008,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) if (static_call(kvm_x86_is_vm_type_supported)(KVM_X86_TDX_VM)) r |= BIT(KVM_X86_TDX_VM); break; + case KVM_CAP_READONLY_MEM: + r = kvm && kvm->readonly_mem_unsupported ? 0 : 1; + break; default: break; } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index ddd4d0f68cdf..7ee7104b4b59 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -597,6 +597,10 @@ struct kvm { unsigned int max_halt_poll_ns; u32 dirty_ring_size; +#ifdef __KVM_HAVE_READONLY_MEM + bool readonly_mem_unsupported; +#endif + bool vm_bugged; }; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 52d40ea75749..63d0c2833913 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1258,12 +1258,14 @@ static void update_memslots(struct kvm_memslots *slots, } } -static int check_memory_region_flags(const struct kvm_userspace_memory_region *mem) +static int check_memory_region_flags(struct kvm *kvm, + const struct kvm_userspace_memory_region *mem) { u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES; #ifdef __KVM_HAVE_READONLY_MEM - valid_flags |= KVM_MEM_READONLY; + if (!kvm->readonly_mem_unsupported) + valid_flags |= KVM_MEM_READONLY; #endif if (mem->flags & ~valid_flags) @@ -1436,7 +1438,7 @@ int __kvm_set_memory_region(struct kvm *kvm, int as_id, id; int r; - r = check_memory_region_flags(mem); + r = check_memory_region_flags(kvm, mem); if (r) return r;