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Date: Wed, 4 Aug 2021 14:44:57 -0400
From: Tianyu Lan <ltykernel@...il.com>
To: kys@...rosoft.com, haiyangz@...rosoft.com, sthemmin@...rosoft.com,
wei.liu@...nel.org, decui@...rosoft.com, tglx@...utronix.de,
mingo@...hat.com, bp@...en8.de, x86@...nel.org, hpa@...or.com,
dave.hansen@...ux.intel.com, luto@...nel.org, peterz@...radead.org,
konrad.wilk@...cle.com, boris.ostrovsky@...cle.com,
jgross@...e.com, sstabellini@...nel.org, joro@...tes.org,
will@...nel.org, davem@...emloft.net, kuba@...nel.org,
jejb@...ux.ibm.com, martin.petersen@...cle.com, arnd@...db.de,
hch@....de, m.szyprowski@...sung.com, robin.murphy@....com,
Tianyu.Lan@...rosoft.com, rppt@...nel.org,
kirill.shutemov@...ux.intel.com, akpm@...ux-foundation.org,
brijesh.singh@....com, thomas.lendacky@....com, pgonda@...gle.com,
david@...hat.com, krish.sadhukhan@...cle.com, saravanand@...com,
aneesh.kumar@...ux.ibm.com, xen-devel@...ts.xenproject.org,
martin.b.radev@...il.com, ardb@...nel.org, rientjes@...gle.com,
tj@...nel.org, keescook@...omium.org,
michael.h.kelley@...rosoft.com
Cc: iommu@...ts.linux-foundation.org, linux-arch@...r.kernel.org,
linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-scsi@...r.kernel.org, netdev@...r.kernel.org,
vkuznets@...hat.com, parri.andrea@...il.com
Subject: [PATCH V2 01/14] x86/HV: Initialize GHCB page in Isolation VM
From: Tianyu Lan <Tianyu.Lan@...rosoft.com>
Hyper-V 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.
Signed-off-by: Tianyu Lan <Tianyu.Lan@...rosoft.com>
---
arch/x86/hyperv/hv_init.c | 69 +++++++++++++++++++++++++++++++--
arch/x86/include/asm/mshyperv.h | 2 +
include/asm-generic/mshyperv.h | 2 +
3 files changed, 69 insertions(+), 4 deletions(-)
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 4a643a85d570..247df301491f 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>
@@ -42,6 +43,31 @@ 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 (!ms_hyperv.ghcb_base)
+ return -EINVAL;
+
+ /*
+ * GHCB page is allocated by paravisor. The address
+ * returned by MSR_AMD64_SEV_ES_GHCB is above shared
+ * ghcb 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(ms_hyperv.ghcb_base);
+ *ghcb_base = ghcb_va;
+
+ return 0;
+}
+
static int hv_cpu_init(unsigned int cpu)
{
struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
@@ -75,6 +101,8 @@ static int hv_cpu_init(unsigned int cpu)
wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val);
}
+ hyperv_init_ghcb();
+
return 0;
}
@@ -167,6 +195,14 @@ static int hv_cpu_die(unsigned int cpu)
{
struct hv_reenlightenment_control re_ctrl;
unsigned int new_cpu;
+ void **ghcb_va = NULL;
+
+ if (ms_hyperv.ghcb_base) {
+ ghcb_va = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
+ if (*ghcb_va)
+ memunmap(*ghcb_va);
+ *ghcb_va = NULL;
+ }
hv_common_cpu_die(cpu);
@@ -340,9 +376,22 @@ 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;
+
+ if (hv_isolation_type_snp()) {
+ ms_hyperv.ghcb_base = alloc_percpu(void *);
+ if (!ms_hyperv.ghcb_base)
+ goto clean_guest_os_id;
+
+ if (hyperv_init_ghcb()) {
+ free_percpu(ms_hyperv.ghcb_base);
+ ms_hyperv.ghcb_base = NULL;
+ goto clean_guest_os_id;
+ }
+
+ /* Hyper-V requires to write guest os id via ghcb in SNP IVM. */
+ hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id);
}
rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
@@ -403,7 +452,8 @@ 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_vp_assist_page:
kfree(hv_vp_assist_page);
@@ -431,6 +481,9 @@ void hyperv_cleanup(void)
*/
hv_hypercall_pg = NULL;
+ if (ms_hyperv.ghcb_base)
+ free_percpu(ms_hyperv.ghcb_base);
+
/* Reset the hypercall page */
hypercall_msr.as_uint64 = 0;
wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
@@ -506,3 +559,11 @@ 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);
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index adccbc209169..6627cfd2bfba 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -11,6 +11,8 @@
#include <asm/paravirt.h>
#include <asm/mshyperv.h>
+DECLARE_STATIC_KEY_FALSE(isolation_type_snp);
+
typedef int (*hyperv_fill_flush_list_func)(
struct hv_guest_mapping_flush_list *flush,
void *data);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index c1ab6a6e72b5..4269f3174e58 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -36,6 +36,7 @@ struct ms_hyperv_info {
u32 max_lp_index;
u32 isolation_config_a;
u32 isolation_config_b;
+ void __percpu **ghcb_base;
};
extern struct ms_hyperv_info ms_hyperv;
@@ -237,6 +238,7 @@ bool hv_is_hyperv_initialized(void);
bool hv_is_hibernation_supported(void);
enum hv_isolation_type hv_get_isolation_type(void);
bool hv_is_isolation_supported(void);
+bool hv_isolation_type_snp(void);
void hyperv_cleanup(void);
bool hv_query_ext_cap(u64 cap_query);
#else /* CONFIG_HYPERV */
--
2.25.1
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