* Philippe Mathieu-Daudé (philmd@xxxxxxxxxx) 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@xxxxxxxxxx>
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@xxxxxxx>
> - *
> - * 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
>
--
Dr. David Alan Gilbert / dgilbert@xxxxxxxxxx / Manchester, UK
