On 9/21/24 22:36, Pavan Kumar Paluri wrote:
> Move SEV specific kernel command line option parsing support from
> arch/x86/coco/sev/core.c to arch/x86/virt/svm/cmdline.c so that both
> host and guest related SEV command line options can be supported.
>
> No functional changes intended.
>
> Signed-off-by: Pavan Kumar Paluri <papaluri@xxxxxxx>
> Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
> ---
> arch/x86/coco/sev/core.c | 44 -------------------------------
> arch/x86/include/asm/sev-common.h | 29 ++++++++++++++++++++
> arch/x86/virt/svm/Makefile | 1 +
> arch/x86/virt/svm/cmdline.c | 32 ++++++++++++++++++++++
> 4 files changed, 62 insertions(+), 44 deletions(-)
> create mode 100644 arch/x86/virt/svm/cmdline.c
>
...
> diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
> index 98726c2b04f8..adddcf3edaf0 100644
> --- a/arch/x86/include/asm/sev-common.h
> +++ b/arch/x86/include/asm/sev-common.h
> @@ -8,6 +8,8 @@
> #ifndef __ASM_X86_SEV_COMMON_H
> #define __ASM_X86_SEV_COMMON_H
>
> +#include <asm/cache.h>
> +
> #define GHCB_MSR_INFO_POS 0
> #define GHCB_DATA_LOW 12
> #define GHCB_MSR_INFO_MASK (BIT_ULL(GHCB_DATA_LOW) - 1)
> @@ -220,4 +222,31 @@ struct snp_psc_desc {
> #define GHCB_ERR_INVALID_INPUT 5
> #define GHCB_ERR_INVALID_EVENT 6
>
> +struct sev_config {
> + __u64 debug : 1,
> +
> + /*
> + * Indicates when the per-CPU GHCB has been created and registered
> + * and thus can be used by the BSP instead of the early boot GHCB.
> + *
> + * For APs, the per-CPU GHCB is created before they are started
> + * and registered upon startup, so this flag can be used globally
> + * for the BSP and APs.
> + */
> + ghcbs_initialized : 1,
> +
> + /*
> + * Indicates when the per-CPU SVSM CA is to be used instead of the
> + * boot SVSM CA.
> + *
> + * For APs, the per-CPU SVSM CA is created as part of the AP
> + * bringup, so this flag can be used globally for the BSP and APs.
> + */
> + use_cas : 1,
> +
> + __reserved : 61;
> +};
> +
> +extern struct sev_config sev_cfg __read_mostly;
So I believe the "__read_mostly" attribute really needs to be on the
actual declaration of the struct, below, in cmdline.c, right?
You can check and see which section the sev_cfg struct ends up being
placed after a build to verify.
Thanks,
Tom
> +
> #endif
> diff --git a/arch/x86/virt/svm/Makefile b/arch/x86/virt/svm/Makefile
> index ef2a31bdcc70..eca6d71355fa 100644
> --- a/arch/x86/virt/svm/Makefile
> +++ b/arch/x86/virt/svm/Makefile
> @@ -1,3 +1,4 @@
> # SPDX-License-Identifier: GPL-2.0
>
> obj-$(CONFIG_KVM_AMD_SEV) += sev.o
> +obj-$(CONFIG_CPU_SUP_AMD) += cmdline.o
> diff --git a/arch/x86/virt/svm/cmdline.c b/arch/x86/virt/svm/cmdline.c
> new file mode 100644
> index 000000000000..964677ab02d6
> --- /dev/null
> +++ b/arch/x86/virt/svm/cmdline.c
> @@ -0,0 +1,32 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * AMD SVM-SEV command line parsing support
> + *
> + * Copyright (C) 2023 - 2024 Advanced Micro Devices, Inc.
> + *
> + * Author: Michael Roth <michael.roth@xxxxxxx>
> + */
> +
> +#include <linux/string.h>
> +#include <linux/printk.h>
> +
> +#include <asm/sev-common.h>
> +
> +struct sev_config sev_cfg;
> +
> +static int __init init_sev_config(char *str)
> +{
> + char *s;
> +
> + while ((s = strsep(&str, ","))) {
> + if (!strcmp(s, "debug")) {
> + sev_cfg.debug = true;
> + continue;
> + }
> +
> + pr_info("SEV command-line option '%s' was not recognized\n", s);
> + }
> +
> + return 1;
> +}
> +__setup("sev=", init_sev_config);
