Hello Tom,
On 9/25/2024 10:57 AM, Tom Lendacky wrote:
> 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
>>
>
...
>> +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?
>
Yes, I will move this attribute to cmdline.c
> You can check and see which section the sev_cfg struct ends up being
> placed after a build to verify.
>
It is placed in .data.readmostly section.
0000000000000000 g O .data..read_mostly 0000000000000008 sev_cfg
> Thanks,
> Tom
>
Thanks for the review,
Pavan
>> +
>> #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);
