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x86/Hyper-V: Add new hvcall guest address host visibility support
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Add new hvcall guest address host visibility and make buffer
visible to host when create gpadl.

Signed-off-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
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Tianyu Lan authored and Tianyu Lan committed Jan 15, 2021
1 parent e697bc5 commit deb6dc9
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Showing 6 changed files with 623 additions and 20 deletions.
17 changes: 17 additions & 0 deletions arch/x86/include/asm/hyperv-tlfs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -105,6 +105,9 @@
#define HV_X64_DEBUGGING BIT(11)
#define HV_X64_CPU_POWER_MANAGEMENT BIT(12)

/* Isolation VM flag */
#define HV_X64_PARTITION_ISOLATION BIT(22)

/*
* Feature identification. EDX indicates which miscellaneous features
* are available to the partition.
Expand Down Expand Up @@ -382,6 +385,7 @@ struct hv_tsc_emulation_status {
#define HVCALL_SIGNAL_EVENT 0x005d
#define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE 0x00af
#define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST 0x00b0
#define HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY 0x00db

#define HV_X64_MSR_VP_ASSIST_PAGE_ENABLE 0x00000001
#define HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT 12
Expand Down Expand Up @@ -912,4 +916,17 @@ struct hv_tlb_flush_ex {
struct hv_partition_assist_pg {
u32 tlb_lock_count;
};
/* All input parameters should be in single page. */
#define HV_MAX_MODIFY_GPA_REP_COUNT \
((PAGE_SIZE - 2 * sizeof(u64)) / (sizeof(u64)))

/* HvCallModifySparseGpaPageHostVisibility hypercall */
struct hv_input_modify_sparse_gpa_page_host_visibility {
u64 partition_id;
u32 host_visibility:2;
u32 reserved0:30;
u32 reserved1;
u64 gpa_page_list[HV_MAX_MODIFY_GPA_REP_COUNT];
} __packed;

#endif
6 changes: 6 additions & 0 deletions arch/x86/include/asm/mshyperv.h
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Original file line number Diff line number Diff line change
Expand Up @@ -239,6 +239,7 @@ bool hv_vcpu_is_preempted(int vcpu);
static inline void hv_apic_init(void) {}
#endif

int hv_mark_gpa_visibility(u16 count, const u64 pfn[], u32 visibility);
#else /* CONFIG_HYPERV */
static inline void hyperv_init(void) {}
static inline void hyperv_setup_mmu_ops(void) {}
Expand All @@ -262,4 +263,9 @@ static inline int hyperv_flush_guest_mapping_range(u64 as,

#include <asm-generic/mshyperv.h>

static inline bool hv_partition_is_isolated(void)
{
return (ms_hyperv.partition_flags & HV_X64_PARTITION_ISOLATION);
}

#endif
52 changes: 50 additions & 2 deletions arch/x86/kernel/cpu/mshyperv.c
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,8 @@
#include <asm/nmi.h>
#include <clocksource/hyperv_timer.h>

#define HV_PARTITION_ID_SELF ((u64)-1)

struct ms_hyperv_info ms_hyperv;
EXPORT_SYMBOL_GPL(ms_hyperv);

Expand Down Expand Up @@ -224,11 +226,13 @@ static void __init ms_hyperv_init_platform(void)
* Extract the features and hints
*/
ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
ms_hyperv.partition_flags = cpuid_ebx(HYPERV_CPUID_FEATURES);
ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);

pr_info("Hyper-V: features 0x%x, hints 0x%x\n",
ms_hyperv.features, ms_hyperv.hints);

pr_info("Hyper-V: features 0x%x, partition flags: 0x%x, hints 0x%x.\n",
ms_hyperv.features, ms_hyperv.partition_flags, ms_hyperv.hints);

ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS);
ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS);
Expand Down Expand Up @@ -355,6 +359,50 @@ void hv_setup_sched_clock(void *sched_clock)
#endif
}

int hv_mark_gpa_visibility(u16 count, const u64 pfn[], u32 visibility)
{
struct hv_input_modify_sparse_gpa_page_host_visibility **input_pcpu;
struct hv_input_modify_sparse_gpa_page_host_visibility *input;
u16 pages_processed;
u64 hv_status;
unsigned long flags;

/* no-op if partition isolation is not enabled */
if (!hv_partition_is_isolated())
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_input_modify_sparse_gpa_page_host_visibility **)
this_cpu_ptr(hyperv_pcpu_input_arg);
input = *input_pcpu;
if (unlikely(!input)) {
local_irq_restore(flags);
return -1;
}

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_status & HV_HYPERCALL_RESULT_MASK))
return 0;

return -EFAULT;
}
EXPORT_SYMBOL(hv_mark_gpa_visibility);

const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
.name = "Microsoft Hyper-V",
.detect = ms_hyperv_platform,
Expand Down
69 changes: 51 additions & 18 deletions drivers/hv/channel.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -303,8 +303,10 @@ static int create_gpadl_header(void *kbuffer, u32 size,
struct vmbus_channel_gpadl_body *gpadl_body;
struct vmbus_channel_msginfo *msgheader;
struct vmbus_channel_msginfo *msgbody = NULL;
struct vmbus_channel_msginfo *pos = NULL;
struct vmbus_channel_msginfo *tmp = NULL;
u32 msgsize;

int ret = -ENOMEM;
int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;

pagecount = size >> PAGE_SHIFT;
Expand Down Expand Up @@ -339,6 +341,10 @@ static int create_gpadl_header(void *kbuffer, u32 size,
gpadl_header->range[0].pfn_array[i] = virt_to_hvpfn(
kbuffer + PAGE_SIZE * i);
*msginfo = msgheader;
ret = hv_mark_gpa_visibility(i,
gpadl_header->range[0].pfn_array, visibility);
if (ret < 0)
goto nomem;

pfnsum = pfncount;
pfnleft = pagecount - pfncount;
Expand All @@ -360,22 +366,8 @@ static int create_gpadl_header(void *kbuffer, u32 size,
pfncurr * sizeof(u64);
msgbody = kzalloc(msgsize, GFP_KERNEL);

if (!msgbody) {
struct vmbus_channel_msginfo *pos = NULL;
struct vmbus_channel_msginfo *tmp = NULL;
/*
* Free up all the allocated messages.
*/
list_for_each_entry_safe(pos, tmp,
&msgheader->submsglist,
msglistentry) {

list_del(&pos->msglistentry);
kfree(pos);
}

goto nomem;
}
if (!msgbody)
goto Cleanvisibility;

msgbody->msgsize = msgsize;
gpadl_body =
Expand All @@ -390,6 +382,10 @@ static int create_gpadl_header(void *kbuffer, u32 size,
for (i = 0; i < pfncurr; i++)
gpadl_body->pfn[i] = virt_to_hvpfn(
kbuffer + PAGE_SIZE * (pfnsum + i));
ret = hv_mark_gpa_visibility(i, gpadl_body->pfn,
visibility);
if (ret < 0)
goto Cleanvisibility;

/* add to msg header */
list_add_tail(&msgbody->msglistentry,
Expand Down Expand Up @@ -420,14 +416,51 @@ static int create_gpadl_header(void *kbuffer, u32 size,
gpadl_header->range[0].pfn_array[i] = virt_to_hvpfn(
kbuffer + PAGE_SIZE * i);

ret = hv_mark_gpa_visibility(i, gpadl_header->range[0].pfn_array,
visibility);
if (ret < 0)
goto nomem;
*msginfo = msgheader;
}

return 0;

Cleanvisibility:
/*
* Free up all the allocated messages.
*/
list_for_each_entry_safe(pos, tmp,
&msgheader->submsglist,
msglistentry) {

list_del(&pos->msglistentry);
kfree(pos);
}

/* Set host visibility back to not-visible. */
pfnleft = pfnsum;
pfnsum = 0;
while (pfnleft) {
if (pfnleft > pfncount)
pfncurr = pfncount;
else
pfncurr = pfnleft;

for (i = 0; i < pfncurr; i++)
gpadl_body->pfn[i] = virt_to_hvpfn(
kbuffer + PAGE_SIZE * (pfnsum + i));
hv_mark_gpa_visibility(i, gpadl_body->pfn,
VMBUS_PAGE_NOT_VISIBLE);

pfnsum += pfncurr;
pfnleft -= pfncurr;
}

nomem:

kfree(msgheader);
kfree(msgbody);
return -ENOMEM;
return ret;
}

/*
Expand Down
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