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// SPDX-License-Identifier: GPL-2.0
/*
* Hyper-V Isolation VM interface with paravisor and hypervisor
*
* Author:
* Tianyu Lan <Tianyu.Lan@microsoft.com>
*/
#include <linux/types.h>
#include <linux/bitfield.h>
#include <linux/hyperv.h>
#include <linux/types.h>
#include <linux/bitfield.h>
#include <linux/slab.h>
#include <asm/svm.h>
#include <asm/sev.h>
#include <asm/io.h>
#include <asm/mshyperv.h>
#include <asm/hypervisor.h>
#ifdef CONFIG_AMD_MEM_ENCRYPT
union hv_ghcb {
struct ghcb ghcb;
} __packed __aligned(HV_HYP_PAGE_SIZE);
void hv_ghcb_msr_write(u64 msr, u64 value)
{
union hv_ghcb *hv_ghcb;
void **ghcb_base;
unsigned long flags;
struct es_em_ctxt ctxt;
if (!hv_ghcb_pg)
return;
WARN_ON(in_nmi());
local_irq_save(flags);
ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
hv_ghcb = (union hv_ghcb *)*ghcb_base;
if (!hv_ghcb) {
local_irq_restore(flags);
return;
}
ghcb_set_rcx(&hv_ghcb->ghcb, msr);
ghcb_set_rax(&hv_ghcb->ghcb, lower_32_bits(value));
ghcb_set_rdx(&hv_ghcb->ghcb, upper_32_bits(value));
if (sev_es_ghcb_hv_call(&hv_ghcb->ghcb, false, &ctxt,
SVM_EXIT_MSR, 1, 0))
pr_warn("Fail to write msr via ghcb %llx.\n", msr);
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(hv_ghcb_msr_write);
void hv_ghcb_msr_read(u64 msr, u64 *value)
{
union hv_ghcb *hv_ghcb;
void **ghcb_base;
unsigned long flags;
struct es_em_ctxt ctxt;
/* Check size of union hv_ghcb here. */
BUILD_BUG_ON(sizeof(union hv_ghcb) != HV_HYP_PAGE_SIZE);
if (!hv_ghcb_pg)
return;
WARN_ON(in_nmi());
local_irq_save(flags);
ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
hv_ghcb = (union hv_ghcb *)*ghcb_base;
if (!hv_ghcb) {
local_irq_restore(flags);
return;
}
ghcb_set_rcx(&hv_ghcb->ghcb, msr);
if (sev_es_ghcb_hv_call(&hv_ghcb->ghcb, false, &ctxt,
SVM_EXIT_MSR, 0, 0))
pr_warn("Fail to read msr via ghcb %llx.\n", msr);
else
*value = (u64)lower_32_bits(hv_ghcb->ghcb.save.rax)
| ((u64)lower_32_bits(hv_ghcb->ghcb.save.rdx) << 32);
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(hv_ghcb_msr_read);
#endif
enum hv_isolation_type hv_get_isolation_type(void)
{
if (!(ms_hyperv.priv_high & HV_ISOLATION))
return HV_ISOLATION_TYPE_NONE;
return FIELD_GET(HV_ISOLATION_TYPE, ms_hyperv.isolation_config_b);
}
EXPORT_SYMBOL_GPL(hv_get_isolation_type);
/*
* hv_is_isolation_supported - Check system runs in the Hyper-V
* isolation VM.
*/
bool hv_is_isolation_supported(void)
{
if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
return false;
if (!hypervisor_is_type(X86_HYPER_MS_HYPERV))
return false;
return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
}
DEFINE_STATIC_KEY_FALSE(isolation_type_snp);
/*
* hv_isolation_type_snp - Check system runs in the AMD SEV-SNP based
* isolation VM.
*/
bool hv_isolation_type_snp(void)
{
return static_branch_unlikely(&isolation_type_snp);
}
/*
* hv_mark_gpa_visibility - Set pages visible to host via hvcall.
*
* In Isolation VM, all guest memory is encrypted from host and guest
* needs to set memory visible to host via hvcall before sharing memory
* with host.
*/
static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
enum hv_mem_host_visibility visibility)
{
struct hv_gpa_range_for_visibility **input_pcpu, *input;
u16 pages_processed;
u64 hv_status;
unsigned long flags;
/* no-op if partition isolation is not enabled */
if (!hv_is_isolation_supported())
return 0;
if (count > HV_MAX_MODIFY_GPA_REP_COUNT) {
pr_err("Hyper-V: GPA count:%d exceeds supported:%lu\n", count,
HV_MAX_MODIFY_GPA_REP_COUNT);
return -EINVAL;
}
local_irq_save(flags);
input_pcpu = (struct hv_gpa_range_for_visibility **)
this_cpu_ptr(hyperv_pcpu_input_arg);
input = *input_pcpu;
if (unlikely(!input)) {
local_irq_restore(flags);
return -EINVAL;
}
input->partition_id = HV_PARTITION_ID_SELF;
input->host_visibility = visibility;
input->reserved0 = 0;
input->reserved1 = 0;
memcpy((void *)input->gpa_page_list, pfn, count * sizeof(*pfn));
hv_status = hv_do_rep_hypercall(
HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY, count,
0, input, &pages_processed);
local_irq_restore(flags);
if (hv_result_success(hv_status))
return 0;
else
return -EFAULT;
}
/*
* hv_set_mem_host_visibility - Set specified memory visible to host.
*
* In Isolation VM, all guest memory is encrypted from host and guest
* needs to set memory visible to host via hvcall before sharing memory
* with host. This function works as wrap of hv_mark_gpa_visibility()
* with memory base and size.
*/
int hv_set_mem_host_visibility(unsigned long kbuffer, int pagecount, bool visible)
{
enum hv_mem_host_visibility visibility = visible ?
VMBUS_PAGE_VISIBLE_READ_WRITE : VMBUS_PAGE_NOT_VISIBLE;
u64 *pfn_array;
int ret = 0;
int i, pfn;
if (!hv_is_isolation_supported() || !hv_hypercall_pg)
return 0;
pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
if (!pfn_array)
return -ENOMEM;
for (i = 0, pfn = 0; i < pagecount; i++) {
pfn_array[pfn] = virt_to_hvpfn((void *)kbuffer + i * HV_HYP_PAGE_SIZE);
pfn++;
if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
ret = hv_mark_gpa_visibility(pfn, pfn_array,
visibility);
if (ret)
goto err_free_pfn_array;
pfn = 0;
}
}
err_free_pfn_array:
kfree(pfn_array);
return ret;
}
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