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authorTianyu Lan <Tianyu.Lan@microsoft.com>2021-10-25 08:21:06 -0400
committerWei Liu <wei.liu@kernel.org>2021-10-28 10:47:52 +0000
commit0cc4f6d9f0b9f20f3f1e1149bdb6737c0b4e134a (patch)
tree6b38683b18f98bd2a5950149d5d2d29793833cdb /arch/x86/hyperv
parente82f2069b52fb350f4ea568957dcc5c9f3649999 (diff)
x86/hyperv: Initialize GHCB page in Isolation VM
Hyperv exposes GHCB page via SEV ES GHCB MSR for SNP guest to communicate with hypervisor. Map GHCB page for all cpus to read/write MSR register and submit hvcall request via ghcb page. Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com> Link: https://lore.kernel.org/r/20211025122116.264793-2-ltykernel@gmail.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'arch/x86/hyperv')
-rw-r--r--arch/x86/hyperv/hv_init.c68
1 files changed, 61 insertions, 7 deletions
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 708a2712a516..a7e922755ad1 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -20,6 +20,7 @@
#include <linux/kexec.h>
#include <linux/version.h>
#include <linux/vmalloc.h>
+#include <linux/io.h>
#include <linux/mm.h>
#include <linux/hyperv.h>
#include <linux/slab.h>
@@ -36,12 +37,42 @@ EXPORT_SYMBOL_GPL(hv_current_partition_id);
void *hv_hypercall_pg;
EXPORT_SYMBOL_GPL(hv_hypercall_pg);
+void __percpu **hv_ghcb_pg;
+
/* Storage to save the hypercall page temporarily for hibernation */
static void *hv_hypercall_pg_saved;
struct hv_vp_assist_page **hv_vp_assist_page;
EXPORT_SYMBOL_GPL(hv_vp_assist_page);
+static int hyperv_init_ghcb(void)
+{
+ u64 ghcb_gpa;
+ void *ghcb_va;
+ void **ghcb_base;
+
+ if (!hv_isolation_type_snp())
+ return 0;
+
+ if (!hv_ghcb_pg)
+ return -EINVAL;
+
+ /*
+ * GHCB page is allocated by paravisor. The address
+ * returned by MSR_AMD64_SEV_ES_GHCB is above shared
+ * memory boundary and map it here.
+ */
+ rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
+ ghcb_va = memremap(ghcb_gpa, HV_HYP_PAGE_SIZE, MEMREMAP_WB);
+ if (!ghcb_va)
+ return -ENOMEM;
+
+ ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
+ *ghcb_base = ghcb_va;
+
+ return 0;
+}
+
static int hv_cpu_init(unsigned int cpu)
{
union hv_vp_assist_msr_contents msr = { 0 };
@@ -85,7 +116,7 @@ static int hv_cpu_init(unsigned int cpu)
}
}
- return 0;
+ return hyperv_init_ghcb();
}
static void (*hv_reenlightenment_cb)(void);
@@ -177,6 +208,14 @@ static int hv_cpu_die(unsigned int cpu)
{
struct hv_reenlightenment_control re_ctrl;
unsigned int new_cpu;
+ void **ghcb_va;
+
+ if (hv_ghcb_pg) {
+ ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);
+ if (*ghcb_va)
+ memunmap(*ghcb_va);
+ *ghcb_va = NULL;
+ }
hv_common_cpu_die(cpu);
@@ -366,10 +405,16 @@ void __init hyperv_init(void)
goto common_free;
}
+ if (hv_isolation_type_snp()) {
+ hv_ghcb_pg = alloc_percpu(void *);
+ if (!hv_ghcb_pg)
+ goto free_vp_assist_page;
+ }
+
cpuhp = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/hyperv_init:online",
hv_cpu_init, hv_cpu_die);
if (cpuhp < 0)
- goto free_vp_assist_page;
+ goto free_ghcb_page;
/*
* Setup the hypercall page and enable hypercalls.
@@ -383,10 +428,8 @@ void __init hyperv_init(void)
VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,
VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
__builtin_return_address(0));
- if (hv_hypercall_pg == NULL) {
- wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
- goto remove_cpuhp_state;
- }
+ if (hv_hypercall_pg == NULL)
+ goto clean_guest_os_id;
rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
hypercall_msr.enable = 1;
@@ -456,8 +499,11 @@ void __init hyperv_init(void)
hv_query_ext_cap(0);
return;
-remove_cpuhp_state:
+clean_guest_os_id:
+ wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
cpuhp_remove_state(cpuhp);
+free_ghcb_page:
+ free_percpu(hv_ghcb_pg);
free_vp_assist_page:
kfree(hv_vp_assist_page);
hv_vp_assist_page = NULL;
@@ -559,3 +605,11 @@ bool hv_is_isolation_supported(void)
{
return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
}
+
+DEFINE_STATIC_KEY_FALSE(isolation_type_snp);
+
+bool hv_isolation_type_snp(void)
+{
+ return static_branch_unlikely(&isolation_type_snp);
+}
+EXPORT_SYMBOL_GPL(hv_isolation_type_snp);