leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

x86/sev: Add a sev= cmdline option

Browse Source 
For debugging purposes it is very useful to have a way to see the full
contents of the SNP CPUID table provided to a guest. Add an sev=debug
kernel command-line option to do so.

Also introduce some infrastructure so that additional options can be
specified via sev=option1[,option2] over time in a consistent manner.

  [ bp: Massage, simplify string parsing. ]

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-41-brijesh.singh@amd.com
This commit is contained in:
Michael Roth 2022-03-07 15:33:50 -06:00 committed by Borislav Petkov
parent 30612045e6
commit ba37a1438a
3 changed files with 60 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/admin-guide/kernel-parameters.txt
View File

@ -5308,6 +5308,8 @@
serialnumber [BUGS=X86-32]
sev=option[,option...] [X86-64] See Documentation/x86/x86_64/boot-options.rst
shapers= [NET]
Maximal number of shapers.

14
Documentation/x86/x86_64/boot-options.rst
View File

@ -310,3 +310,17 @@ Miscellaneous
Do not use GB pages for kernel direct mappings.
gbpages
Use GB pages for kernel direct mappings.
AMD SEV (Secure Encrypted Virtualization)
=========================================
Options relating to AMD SEV, specified via the following format:
::
sev=option1[,option2]
The available options are:
debug
Enable debug messages.

44
arch/x86/kernel/sev.c
View File

@ -112,6 +112,13 @@ DEFINE_STATIC_KEY_FALSE(sev_es_enable_key);
static DEFINE_PER_CPU(struct sev_es_save_area *, sev_vmsa);
struct sev_config {
__u64 debug : 1,
__reserved : 63;
};
static struct sev_config sev_cfg __read_mostly;
static __always_inline bool on_vc_stack(struct pt_regs *regs)
{
unsigned long sp = regs->sp;
@ -2042,6 +2049,23 @@ void __init snp_abort(void)
sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
}
static void dump_cpuid_table(void)
{
const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table();
int i = 0;
pr_info("count=%d reserved=0x%x reserved2=0x%llx\n",
cpuid_table->count, cpuid_table->__reserved1, cpuid_table->__reserved2);
for (i = 0; i < SNP_CPUID_COUNT_MAX; i++) {
const struct snp_cpuid_fn *fn = &cpuid_table->fn[i];
pr_info("index=%3d fn=0x%08x subfn=0x%08x: eax=0x%08x ebx=0x%08x ecx=0x%08x edx=0x%08x xcr0_in=0x%016llx xss_in=0x%016llx reserved=0x%016llx\n",
i, fn->eax_in, fn->ecx_in, fn->eax, fn->ebx, fn->ecx,
fn->edx, fn->xcr0_in, fn->xss_in, fn->__reserved);
}
}
/*
* It is useful from an auditing/testing perspective to provide an easy way
* for the guest owner to know that the CPUID table has been initialized as
@ -2059,6 +2083,26 @@ static int __init report_cpuid_table(void)
pr_info("Using SNP CPUID table, %d entries present.\n",
cpuid_table->count);
if (sev_cfg.debug)
dump_cpuid_table();
return 0;
}
arch_initcall(report_cpuid_table);
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);