[RFC PATCH V3 02/11] x86/HV: Initialize shared memory boundary in the Isolation VM.

[Tianyu Lan <ltykernel@xxxxxxxxx>]

From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>

Hyper-V also 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.

Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
---
 arch/x86/kernel/cpu/mshyperv.c |  2 ++
 include/asm-generic/mshyperv.h | 12 +++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 22f13343b5da..d1ca36224657 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -320,6 +320,8 @@ 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 =
+                       (u64)1 << 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 3ae56a29594f..2914e27b0429 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -34,8 +34,18 @@ 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 Reserved11 : 1;
+                       u32 shared_gpa_boundary_active : 1;
+                       u32 shared_gpa_boundary_bits : 6;
+                       u32 Reserved12 : 20;
+               };
+       };
        void  __percpu **ghcb_base;
+       u64 shared_gpa_boundary;
 };
 extern struct ms_hyperv_info ms_hyperv;
 
-- 
2.25.1