x86/hyperv: Initialize shared memory boundary in the Isolation VM.

Hyper-V exposes shared memory boundary via cpuid
HYPERV_CPUID_ISOLATION_CONFIG and store it in the
shared_gpa_boundary of ms_hyperv struct. This prepares
to share memory with host for SNP guest.

Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Link: https://lore.kernel.org/r/20211025122116.264793-3-ltykernel@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index b09ade3..4794b71 100644 (file)
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -313,6 +313,8 @@ static void __init ms_hyperv_init_platform(void)
        if (ms_hyperv.priv_high & HV_ISOLATION) {
                ms_hyperv.isolation_config_a = cpuid_eax(HYPERV_CPUID_ISOLATION_CONFIG);
                ms_hyperv.isolation_config_b = cpuid_ebx(HYPERV_CPUID_ISOLATION_CONFIG);
+               ms_hyperv.shared_gpa_boundary =
+                       BIT_ULL(ms_hyperv.shared_gpa_boundary_bits);
 
                pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
                        ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);

diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 2d88aa8..a8ac497 100644 (file)
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -35,7 +35,17 @@ struct ms_hyperv_info {
        u32 max_vp_index;
        u32 max_lp_index;
        u32 isolation_config_a;
-       u32 isolation_config_b;
+       union {
+               u32 isolation_config_b;
+               struct {
+                       u32 cvm_type : 4;
+                       u32 reserved1 : 1;
+                       u32 shared_gpa_boundary_active : 1;
+                       u32 shared_gpa_boundary_bits : 6;
+                       u32 reserved2 : 20;
+               };
+       };
+       u64 shared_gpa_boundary;
 };
 extern struct ms_hyperv_info ms_hyperv;