| Message ID | 20211007161716.453984-17-philmd@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | target/i386/sev: Housekeeping SEV + measured Linux SEV guest | expand |
* Philippe Mathieu-Daudé (philmd@redhat.com) wrote: > Only declare sev_enabled() and sev_es_enabled() when CONFIG_SEV is > set, to allow the compiler to elide unused code. Remove unnecessary > stubs. > > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> What makes it allowed to *rely* on the compiler eliding calls? Dave > --- > target/i386/sev.h | 14 ++++++++++++-- > target/i386/cpu.c | 13 +++++++------ > target/i386/sev-stub.c | 41 ----------------------------------------- > target/i386/meson.build | 2 +- > 4 files changed, 20 insertions(+), 50 deletions(-) > delete mode 100644 target/i386/sev-stub.c > > diff --git a/target/i386/sev.h b/target/i386/sev.h > index c96072bf78d..d9548e3e642 100644 > --- a/target/i386/sev.h > +++ b/target/i386/sev.h > @@ -14,6 +14,10 @@ > #ifndef QEMU_SEV_I386_H > #define QEMU_SEV_I386_H > > +#ifndef CONFIG_USER_ONLY > +#include CONFIG_DEVICES /* CONFIG_SEV */ > +#endif > + > #include "exec/confidential-guest-support.h" > #include "qapi/qapi-types-misc-target.h" > > @@ -35,8 +39,14 @@ typedef struct SevKernelLoaderContext { > size_t cmdline_size; > } SevKernelLoaderContext; > > -bool sev_enabled(void); > -extern bool sev_es_enabled(void); > +#ifdef CONFIG_SEV > + bool sev_enabled(void); > +bool sev_es_enabled(void); > +#else > +#define sev_enabled() 0 > +#define sev_es_enabled() 0 > +#endif > + > extern SevInfo *sev_get_info(void); > extern uint32_t sev_get_cbit_position(void); > extern uint32_t sev_get_reduced_phys_bits(void); > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index 8289dc87bd5..fc3ed80ef1e 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -5764,12 +5764,13 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, > *edx = 0; > break; > case 0x8000001F: > - *eax = sev_enabled() ? 0x2 : 0; > - *eax |= sev_es_enabled() ? 0x8 : 0; > - *ebx = sev_get_cbit_position(); > - *ebx |= sev_get_reduced_phys_bits() << 6; > - *ecx = 0; > - *edx = 0; > + *eax = *ebx = *ecx = *edx = 0; > + if (sev_enabled()) { > + *eax = 0x2; > + *eax |= sev_es_enabled() ? 0x8 : 0; > + *ebx = sev_get_cbit_position(); > + *ebx |= sev_get_reduced_phys_bits() << 6; > + } > break; > default: > /* reserved values: zero */ > diff --git a/target/i386/sev-stub.c b/target/i386/sev-stub.c > deleted file mode 100644 > index 7e8b6f9a259..00000000000 > --- a/target/i386/sev-stub.c > +++ /dev/null > @@ -1,41 +0,0 @@ > -/* > - * QEMU SEV stub > - * > - * Copyright Advanced Micro Devices 2018 > - * > - * Authors: > - * Brijesh Singh <brijesh.singh@amd.com> > - * > - * This work is licensed under the terms of the GNU GPL, version 2 or later. > - * See the COPYING file in the top-level directory. > - * > - */ > - > -#include "qemu/osdep.h" > -#include "qapi/error.h" > -#include "sev.h" > - > -bool sev_enabled(void) > -{ > - return false; > -} > - > -uint32_t sev_get_cbit_position(void) > -{ > - return 0; > -} > - > -uint32_t sev_get_reduced_phys_bits(void) > -{ > - return 0; > -} > - > -bool sev_es_enabled(void) > -{ > - return false; > -} > - > -bool sev_add_kernel_loader_hashes(SevKernelLoaderContext *ctx, Error **errp) > -{ > - g_assert_not_reached(); > -} > diff --git a/target/i386/meson.build b/target/i386/meson.build > index a4f45c3ec1d..ae38dc95635 100644 > --- a/target/i386/meson.build > +++ b/target/i386/meson.build > @@ -6,7 +6,7 @@ > 'xsave_helper.c', > 'cpu-dump.c', > )) > -i386_ss.add(when: 'CONFIG_SEV', if_true: files('host-cpu.c'), if_false: files('sev-stub.c')) > +i386_ss.add(when: 'CONFIG_SEV', if_true: files('host-cpu.c')) > > # x86 cpu type > i386_ss.add(when: 'CONFIG_KVM', if_true: files('host-cpu.c')) > -- > 2.31.1 >
On 10/7/21 19:07, Dr. David Alan Gilbert wrote: > * Philippe Mathieu-Daudé (philmd@redhat.com) wrote: >> Only declare sev_enabled() and sev_es_enabled() when CONFIG_SEV is >> set, to allow the compiler to elide unused code. Remove unnecessary >> stubs. >> >> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> > > What makes it allowed to *rely* on the compiler eliding calls? I am not aware of a particular requirement on the compiler for code elision, however we already use this syntax: $ git grep -A4 'ifdef CONFIG_' include/sysemu/ ... include/sysemu/tcg.h:11:#ifdef CONFIG_TCG include/sysemu/tcg.h-12-extern bool tcg_allowed; include/sysemu/tcg.h-13-#define tcg_enabled() (tcg_allowed) include/sysemu/tcg.h-14-#else include/sysemu/tcg.h-15-#define tcg_enabled() 0 ... Cc'ing Richard/Eric/Daniel who have more experience with compiler features in case they can enlighten me here. >> --- >> target/i386/sev.h | 14 ++++++++++++-- >> target/i386/cpu.c | 13 +++++++------ >> target/i386/sev-stub.c | 41 ----------------------------------------- >> target/i386/meson.build | 2 +- >> 4 files changed, 20 insertions(+), 50 deletions(-) >> delete mode 100644 target/i386/sev-stub.c >> >> diff --git a/target/i386/sev.h b/target/i386/sev.h >> index c96072bf78d..d9548e3e642 100644 >> --- a/target/i386/sev.h >> +++ b/target/i386/sev.h >> @@ -14,6 +14,10 @@ >> #ifndef QEMU_SEV_I386_H >> #define QEMU_SEV_I386_H >> >> +#ifndef CONFIG_USER_ONLY >> +#include CONFIG_DEVICES /* CONFIG_SEV */ >> +#endif >> + >> #include "exec/confidential-guest-support.h" >> #include "qapi/qapi-types-misc-target.h" >> >> @@ -35,8 +39,14 @@ typedef struct SevKernelLoaderContext { >> size_t cmdline_size; >> } SevKernelLoaderContext; >> >> -bool sev_enabled(void); >> -extern bool sev_es_enabled(void); >> +#ifdef CONFIG_SEV >> + bool sev_enabled(void); >> +bool sev_es_enabled(void); >> +#else >> +#define sev_enabled() 0 >> +#define sev_es_enabled() 0 >> +#endif >> + >> extern SevInfo *sev_get_info(void); >> extern uint32_t sev_get_cbit_position(void); >> extern uint32_t sev_get_reduced_phys_bits(void); >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c >> index 8289dc87bd5..fc3ed80ef1e 100644 >> --- a/target/i386/cpu.c >> +++ b/target/i386/cpu.c >> @@ -5764,12 +5764,13 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, >> *edx = 0; >> break; >> case 0x8000001F: >> - *eax = sev_enabled() ? 0x2 : 0; >> - *eax |= sev_es_enabled() ? 0x8 : 0; >> - *ebx = sev_get_cbit_position(); >> - *ebx |= sev_get_reduced_phys_bits() << 6; >> - *ecx = 0; >> - *edx = 0; >> + *eax = *ebx = *ecx = *edx = 0; >> + if (sev_enabled()) { >> + *eax = 0x2; >> + *eax |= sev_es_enabled() ? 0x8 : 0; >> + *ebx = sev_get_cbit_position(); >> + *ebx |= sev_get_reduced_phys_bits() << 6; >> + } >> break; >> default: >> /* reserved values: zero */ >> diff --git a/target/i386/sev-stub.c b/target/i386/sev-stub.c >> deleted file mode 100644 >> index 7e8b6f9a259..00000000000 >> --- a/target/i386/sev-stub.c >> +++ /dev/null >> @@ -1,41 +0,0 @@ >> -/* >> - * QEMU SEV stub >> - * >> - * Copyright Advanced Micro Devices 2018 >> - * >> - * Authors: >> - * Brijesh Singh <brijesh.singh@amd.com> >> - * >> - * This work is licensed under the terms of the GNU GPL, version 2 or later. >> - * See the COPYING file in the top-level directory. >> - * >> - */ >> - >> -#include "qemu/osdep.h" >> -#include "qapi/error.h" >> -#include "sev.h" >> - >> -bool sev_enabled(void) >> -{ >> - return false; >> -} >> - >> -uint32_t sev_get_cbit_position(void) >> -{ >> - return 0; >> -} >> - >> -uint32_t sev_get_reduced_phys_bits(void) >> -{ >> - return 0; >> -} >> - >> -bool sev_es_enabled(void) >> -{ >> - return false; >> -} >> - >> -bool sev_add_kernel_loader_hashes(SevKernelLoaderContext *ctx, Error **errp) >> -{ >> - g_assert_not_reached(); >> -} >> diff --git a/target/i386/meson.build b/target/i386/meson.build >> index a4f45c3ec1d..ae38dc95635 100644 >> --- a/target/i386/meson.build >> +++ b/target/i386/meson.build >> @@ -6,7 +6,7 @@ >> 'xsave_helper.c', >> 'cpu-dump.c', >> )) >> -i386_ss.add(when: 'CONFIG_SEV', if_true: files('host-cpu.c'), if_false: files('sev-stub.c')) >> +i386_ss.add(when: 'CONFIG_SEV', if_true: files('host-cpu.c')) >> >> # x86 cpu type >> i386_ss.add(when: 'CONFIG_KVM', if_true: files('host-cpu.c')) >> -- >> 2.31.1 >>
* Philippe Mathieu-Daudé (philmd@redhat.com) wrote: > On 10/7/21 19:07, Dr. David Alan Gilbert wrote: > > * Philippe Mathieu-Daudé (philmd@redhat.com) wrote: > >> Only declare sev_enabled() and sev_es_enabled() when CONFIG_SEV is > >> set, to allow the compiler to elide unused code. Remove unnecessary > >> stubs. > >> > >> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> > > > > What makes it allowed to *rely* on the compiler eliding calls? > > I am not aware of a particular requirement on the compiler for code > elision, however we already use this syntax: > > $ git grep -A4 'ifdef CONFIG_' include/sysemu/ > ... > include/sysemu/tcg.h:11:#ifdef CONFIG_TCG > include/sysemu/tcg.h-12-extern bool tcg_allowed; > include/sysemu/tcg.h-13-#define tcg_enabled() (tcg_allowed) > include/sysemu/tcg.h-14-#else > include/sysemu/tcg.h-15-#define tcg_enabled() 0 So that I'm fine with, the bit I'm more worried about is the bit where inside the if () we call functions (like sev_get_cbit_position ) which we know the compiler will elide; I'm sure any sane compiler will, but..... Looking at your example, in cpu.c there's still places that ifdef around areas with tcg_enabled. Dave > ... > > Cc'ing Richard/Eric/Daniel who have more experience with compiler > features in case they can enlighten me here. > > >> --- > >> target/i386/sev.h | 14 ++++++++++++-- > >> target/i386/cpu.c | 13 +++++++------ > >> target/i386/sev-stub.c | 41 ----------------------------------------- > >> target/i386/meson.build | 2 +- > >> 4 files changed, 20 insertions(+), 50 deletions(-) > >> delete mode 100644 target/i386/sev-stub.c > >> > >> diff --git a/target/i386/sev.h b/target/i386/sev.h > >> index c96072bf78d..d9548e3e642 100644 > >> --- a/target/i386/sev.h > >> +++ b/target/i386/sev.h > >> @@ -14,6 +14,10 @@ > >> #ifndef QEMU_SEV_I386_H > >> #define QEMU_SEV_I386_H > >> > >> +#ifndef CONFIG_USER_ONLY > >> +#include CONFIG_DEVICES /* CONFIG_SEV */ > >> +#endif > >> + > >> #include "exec/confidential-guest-support.h" > >> #include "qapi/qapi-types-misc-target.h" > >> > >> @@ -35,8 +39,14 @@ typedef struct SevKernelLoaderContext { > >> size_t cmdline_size; > >> } SevKernelLoaderContext; > >> > >> -bool sev_enabled(void); > >> -extern bool sev_es_enabled(void); > >> +#ifdef CONFIG_SEV > >> + bool sev_enabled(void); > >> +bool sev_es_enabled(void); > >> +#else > >> +#define sev_enabled() 0 > >> +#define sev_es_enabled() 0 > >> +#endif > >> + > >> extern SevInfo *sev_get_info(void); > >> extern uint32_t sev_get_cbit_position(void); > >> extern uint32_t sev_get_reduced_phys_bits(void); > >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c > >> index 8289dc87bd5..fc3ed80ef1e 100644 > >> --- a/target/i386/cpu.c > >> +++ b/target/i386/cpu.c > >> @@ -5764,12 +5764,13 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, > >> *edx = 0; > >> break; > >> case 0x8000001F: > >> - *eax = sev_enabled() ? 0x2 : 0; > >> - *eax |= sev_es_enabled() ? 0x8 : 0; > >> - *ebx = sev_get_cbit_position(); > >> - *ebx |= sev_get_reduced_phys_bits() << 6; > >> - *ecx = 0; > >> - *edx = 0; > >> + *eax = *ebx = *ecx = *edx = 0; > >> + if (sev_enabled()) { > >> + *eax = 0x2; > >> + *eax |= sev_es_enabled() ? 0x8 : 0; > >> + *ebx = sev_get_cbit_position(); > >> + *ebx |= sev_get_reduced_phys_bits() << 6; > >> + } > >> break; > >> default: > >> /* reserved values: zero */ > >> diff --git a/target/i386/sev-stub.c b/target/i386/sev-stub.c > >> deleted file mode 100644 > >> index 7e8b6f9a259..00000000000 > >> --- a/target/i386/sev-stub.c > >> +++ /dev/null > >> @@ -1,41 +0,0 @@ > >> -/* > >> - * QEMU SEV stub > >> - * > >> - * Copyright Advanced Micro Devices 2018 > >> - * > >> - * Authors: > >> - * Brijesh Singh <brijesh.singh@amd.com> > >> - * > >> - * This work is licensed under the terms of the GNU GPL, version 2 or later. > >> - * See the COPYING file in the top-level directory. > >> - * > >> - */ > >> - > >> -#include "qemu/osdep.h" > >> -#include "qapi/error.h" > >> -#include "sev.h" > >> - > >> -bool sev_enabled(void) > >> -{ > >> - return false; > >> -} > >> - > >> -uint32_t sev_get_cbit_position(void) > >> -{ > >> - return 0; > >> -} > >> - > >> -uint32_t sev_get_reduced_phys_bits(void) > >> -{ > >> - return 0; > >> -} > >> - > >> -bool sev_es_enabled(void) > >> -{ > >> - return false; > >> -} > >> - > >> -bool sev_add_kernel_loader_hashes(SevKernelLoaderContext *ctx, Error **errp) > >> -{ > >> - g_assert_not_reached(); > >> -} > >> diff --git a/target/i386/meson.build b/target/i386/meson.build > >> index a4f45c3ec1d..ae38dc95635 100644 > >> --- a/target/i386/meson.build > >> +++ b/target/i386/meson.build > >> @@ -6,7 +6,7 @@ > >> 'xsave_helper.c', > >> 'cpu-dump.c', > >> )) > >> -i386_ss.add(when: 'CONFIG_SEV', if_true: files('host-cpu.c'), if_false: files('sev-stub.c')) > >> +i386_ss.add(when: 'CONFIG_SEV', if_true: files('host-cpu.c')) > >> > >> # x86 cpu type > >> i386_ss.add(when: 'CONFIG_KVM', if_true: files('host-cpu.c')) > >> -- > >> 2.31.1 > >> >
On Thu, Oct 07, 2021 at 07:18:04PM +0200, Philippe Mathieu-Daudé wrote: > On 10/7/21 19:07, Dr. David Alan Gilbert wrote: > > * Philippe Mathieu-Daudé (philmd@redhat.com) wrote: > >> Only declare sev_enabled() and sev_es_enabled() when CONFIG_SEV is > >> set, to allow the compiler to elide unused code. Remove unnecessary > >> stubs. > >> > >> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> > > > > What makes it allowed to *rely* on the compiler eliding calls? > > I am not aware of a particular requirement on the compiler for code > elision, however we already use this syntax: Maybe I'm mis-understanding David's question, but I'm not sure it matters whether the compiler elides the code or not. IIUC, with the old code using stubs it is unlikely to be elided at all. With the new code it will probably be elided, but if it isn't, then it is no worse than the code its replacing. Or am I mis-understanding David's question ? > $ git grep -A4 'ifdef CONFIG_' include/sysemu/ > ... > include/sysemu/tcg.h:11:#ifdef CONFIG_TCG > include/sysemu/tcg.h-12-extern bool tcg_allowed; > include/sysemu/tcg.h-13-#define tcg_enabled() (tcg_allowed) > include/sysemu/tcg.h-14-#else > include/sysemu/tcg.h-15-#define tcg_enabled() 0 > ... > > Cc'ing Richard/Eric/Daniel who have more experience with compiler > features in case they can enlighten me here. I'd say my general view is we are free to use features explicitly supported by our designated compilers. We should avoid relying on undefined compiler behaviour for funtional results in QEMU. We can rely on our designated compilers to optimize certain code patterns, as long as its purely for performance benefits, not functional benefits, since optimizations are not guaranteed and users can turn them off too. Regards, Daniel
On Thu, Oct 07, 2021 at 06:17:09PM +0200, Philippe Mathieu-Daudé wrote: > Only declare sev_enabled() and sev_es_enabled() when CONFIG_SEV is > set, to allow the compiler to elide unused code. Remove unnecessary > stubs. > > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> > --- > target/i386/sev.h | 14 ++++++++++++-- > target/i386/cpu.c | 13 +++++++------ > target/i386/sev-stub.c | 41 ----------------------------------------- > target/i386/meson.build | 2 +- > 4 files changed, 20 insertions(+), 50 deletions(-) > delete mode 100644 target/i386/sev-stub.c > > diff --git a/target/i386/sev.h b/target/i386/sev.h > index c96072bf78d..d9548e3e642 100644 > --- a/target/i386/sev.h > +++ b/target/i386/sev.h > @@ -14,6 +14,10 @@ > #ifndef QEMU_SEV_I386_H > #define QEMU_SEV_I386_H > > +#ifndef CONFIG_USER_ONLY > +#include CONFIG_DEVICES /* CONFIG_SEV */ > +#endif > + > #include "exec/confidential-guest-support.h" > #include "qapi/qapi-types-misc-target.h" > > @@ -35,8 +39,14 @@ typedef struct SevKernelLoaderContext { > size_t cmdline_size; > } SevKernelLoaderContext; > > -bool sev_enabled(void); > -extern bool sev_es_enabled(void); > +#ifdef CONFIG_SEV > + bool sev_enabled(void); > +bool sev_es_enabled(void); > +#else Is that leading space on the sev_enabled() line intentional? > +#define sev_enabled() 0 > +#define sev_es_enabled() 0 > +#endif > + This allows an optimizing compiler to elide code, but does not require that the elision worked. The real test is whether there is a link error when functions that are only called inside what we hope is elided have no stub. > extern SevInfo *sev_get_info(void); > extern uint32_t sev_get_cbit_position(void); > extern uint32_t sev_get_reduced_phys_bits(void); > diff --git a/target/i386/cpu.c b/target/i386/cpu.c > index 8289dc87bd5..fc3ed80ef1e 100644 > --- a/target/i386/cpu.c > +++ b/target/i386/cpu.c > @@ -5764,12 +5764,13 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, > *edx = 0; > break; > case 0x8000001F: > - *eax = sev_enabled() ? 0x2 : 0; > - *eax |= sev_es_enabled() ? 0x8 : 0; > - *ebx = sev_get_cbit_position(); > - *ebx |= sev_get_reduced_phys_bits() << 6; > - *ecx = 0; > - *edx = 0; > + *eax = *ebx = *ecx = *edx = 0; > + if (sev_enabled()) { > + *eax = 0x2; > + *eax |= sev_es_enabled() ? 0x8 : 0; > + *ebx = sev_get_cbit_position(); > + *ebx |= sev_get_reduced_phys_bits() << 6; > + } As long as this compiles in all of our configurations, then the compiler really has elided the calls and we can get rid of the stub. But that's merely because we're relying on our particular gcc or clang compiler behavior, and NOT because it is standardized behavior. On the other hand, I doubt either compiler would break this assumption, as it is probably used in lots of places, even if it is not portable. Since you asked for my opinion, I'm okay giving: Reviewed-by: Eric Blake <eblake@redhat.com>
On 07/10/21 19:22, Dr. David Alan Gilbert wrote: > So that I'm fine with, the bit I'm more worried about is the bit where > inside the if () we call functions (like sev_get_cbit_position ) which > we know the compiler will elide; I'm sure any sane compiler will, > but..... > > Looking at your example, in cpu.c there's still places that ifdef around > areas with tcg_enabled. I think that's just because nobody tried changing it; it should work there as well. Paolo
diff --git a/target/i386/sev.h b/target/i386/sev.h index c96072bf78d..d9548e3e642 100644 --- a/target/i386/sev.h +++ b/target/i386/sev.h @@ -14,6 +14,10 @@ #ifndef QEMU_SEV_I386_H #define QEMU_SEV_I386_H +#ifndef CONFIG_USER_ONLY +#include CONFIG_DEVICES /* CONFIG_SEV */ +#endif + #include "exec/confidential-guest-support.h" #include "qapi/qapi-types-misc-target.h" @@ -35,8 +39,14 @@ typedef struct SevKernelLoaderContext { size_t cmdline_size; } SevKernelLoaderContext; -bool sev_enabled(void); -extern bool sev_es_enabled(void); +#ifdef CONFIG_SEV + bool sev_enabled(void); +bool sev_es_enabled(void); +#else +#define sev_enabled() 0 +#define sev_es_enabled() 0 +#endif + extern SevInfo *sev_get_info(void); extern uint32_t sev_get_cbit_position(void); extern uint32_t sev_get_reduced_phys_bits(void); diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 8289dc87bd5..fc3ed80ef1e 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -5764,12 +5764,13 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, *edx = 0; break; case 0x8000001F: - *eax = sev_enabled() ? 0x2 : 0; - *eax |= sev_es_enabled() ? 0x8 : 0; - *ebx = sev_get_cbit_position(); - *ebx |= sev_get_reduced_phys_bits() << 6; - *ecx = 0; - *edx = 0; + *eax = *ebx = *ecx = *edx = 0; + if (sev_enabled()) { + *eax = 0x2; + *eax |= sev_es_enabled() ? 0x8 : 0; + *ebx = sev_get_cbit_position(); + *ebx |= sev_get_reduced_phys_bits() << 6; + } break; default: /* reserved values: zero */ diff --git a/target/i386/sev-stub.c b/target/i386/sev-stub.c deleted file mode 100644 index 7e8b6f9a259..00000000000 --- a/target/i386/sev-stub.c +++ /dev/null @@ -1,41 +0,0 @@ -/* - * QEMU SEV stub - * - * Copyright Advanced Micro Devices 2018 - * - * Authors: - * Brijesh Singh <brijesh.singh@amd.com> - * - * This work is licensed under the terms of the GNU GPL, version 2 or later. - * See the COPYING file in the top-level directory. - * - */ - -#include "qemu/osdep.h" -#include "qapi/error.h" -#include "sev.h" - -bool sev_enabled(void) -{ - return false; -} - -uint32_t sev_get_cbit_position(void) -{ - return 0; -} - -uint32_t sev_get_reduced_phys_bits(void) -{ - return 0; -} - -bool sev_es_enabled(void) -{ - return false; -} - -bool sev_add_kernel_loader_hashes(SevKernelLoaderContext *ctx, Error **errp) -{ - g_assert_not_reached(); -} diff --git a/target/i386/meson.build b/target/i386/meson.build index a4f45c3ec1d..ae38dc95635 100644 --- a/target/i386/meson.build +++ b/target/i386/meson.build @@ -6,7 +6,7 @@ 'xsave_helper.c', 'cpu-dump.c', )) -i386_ss.add(when: 'CONFIG_SEV', if_true: files('host-cpu.c'), if_false: files('sev-stub.c')) +i386_ss.add(when: 'CONFIG_SEV', if_true: files('host-cpu.c')) # x86 cpu type i386_ss.add(when: 'CONFIG_KVM', if_true: files('host-cpu.c'))
Only declare sev_enabled() and sev_es_enabled() when CONFIG_SEV is set, to allow the compiler to elide unused code. Remove unnecessary stubs. Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> --- target/i386/sev.h | 14 ++++++++++++-- target/i386/cpu.c | 13 +++++++------ target/i386/sev-stub.c | 41 ----------------------------------------- target/i386/meson.build | 2 +- 4 files changed, 20 insertions(+), 50 deletions(-) delete mode 100644 target/i386/sev-stub.c