[PATCH Part2 v6 04/49] x86/sev: set SYSCFG.MFMD

Ashish Kalra
2022-06-20T23:03:08Z

From: Brijesh Singh <brijesh.singh@amd.com>

SEV-SNP FW >= 1.51 requires that SYSCFG.MFMD must be set.

Subsequent CCP patches while require 1.51 as the minimum SEV-SNP
firmware version.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
arch/x86/include/asm/msr-index.h | 3 +++
arch/x86/kernel/sev.c | 24 ++++++++++++++++++++++++
2 files changed, 27 insertions(+)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 57a8280e283a..1e36f16daa56 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -587,6 +587,9 @@
#define MSR_AMD64_SYSCFG_SNP_EN BIT_ULL(MSR_AMD64_SYSCFG_SNP_EN_BIT)
#define MSR_AMD64_SYSCFG_SNP_VMPL_EN_BIT 25
#define MSR_AMD64_SYSCFG_SNP_VMPL_EN BIT_ULL(MSR_AMD64_SYSCFG_SNP_VMPL_EN_BIT)
+#define MSR_AMD64_SYSCFG_MFDM_BIT 19
+#define MSR_AMD64_SYSCFG_MFDM BIT_ULL(MSR_AMD64_SYSCFG_MFDM_BIT)
+
#define MSR_K8_INT_PENDING_MSG 0xc0010055
/* C1E active bits in int pending message */
#define K8_INTP_C1E_ACTIVE_MASK 0x18000000
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 3a233b5d47c5..25c7feb367f6 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -2257,6 +2257,27 @@ static __init void snp_enable(void *arg)
__snp_enable(smp_processor_id());
}

+static int __mfdm_enable(unsigned int cpu)
+{
+ u64 val;
+
+ if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+ return 0;
+
+ rdmsrl(MSR_AMD64_SYSCFG, val);
+
+ val |= MSR_AMD64_SYSCFG_MFDM;
+
+ wrmsrl(MSR_AMD64_SYSCFG, val);
+
+ return 0;
+}
+
+static __init void mfdm_enable(void *arg)
+{
+ __mfdm_enable(smp_processor_id());
+}
+
static bool get_rmptable_info(u64 *start, u64 *len)
{
u64 calc_rmp_sz, rmp_sz, rmp_base, rmp_end, nr_pages;
@@ -2325,6 +2346,9 @@ static __init int __snp_rmptable_init(void)
/* Flush the caches to ensure that data is written before SNP is enabled. */
wbinvd_on_all_cpus();

+ /* MFDM must be enabled on all the CPUs prior to enabling SNP. */
+ on_each_cpu(mfdm_enable, NULL, 1);
+
/* Enable SNP on all CPUs. */
on_each_cpu(snp_enable, NULL, 1);

--
2.25.1