[PATCH 05/17] mshv: SynIC event ring and event flags support

From: Vineeth Pillai
Date: Wed Jun 02 2021 - 13:21:38 EST

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Doorbell is a mechanism by which a parent partition can register for
notification if a specified mmio address is touched by a child partition.
Parent partition can setup the notification by specifying mmio address,
size of the data written(1/2/4/8 bytes) and optionally the data as well.

Hyper-V makes use of an event ring buffer to signal events. This
buffer is implemented as a GPA overlay page. Doorbell notifications are
delivered via this event ring buffer.

Enable SynIC event ring buffer.

While at it, enable SynIC event flags. It is a lightweight inter-partition
communication mechanism to signal events between partitions or from
hypervisor to a partition.

Signed-off-by: Vineeth Pillai <viremana@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/hyperv-tlfs.h | 2 +
drivers/hv/hv_synic.c | 81 +++++++++++++++++++++++++++---
drivers/hv/mshv_main.c | 6 +--
include/asm-generic/hyperv-tlfs.h | 29 +++++++++++
include/linux/mshv.h | 8 ++-
5 files changed, 115 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index 871f5d014ae0..e4b0eea1703e 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -189,6 +189,7 @@ enum hv_isolation_type {
#define HV_REGISTER_SIEFP 0x40000082
#define HV_REGISTER_SIMP 0x40000083
#define HV_REGISTER_EOM 0x40000084
+#define HV_REGISTER_SIRBP 0x40000085
#define HV_REGISTER_SINT0 0x40000090
#define HV_REGISTER_SINT1 0x40000091
#define HV_REGISTER_SINT2 0x40000092
@@ -252,6 +253,7 @@ enum hv_isolation_type {
#define HV_X64_MSR_SIEFP HV_REGISTER_SIEFP
#define HV_X64_MSR_VP_INDEX HV_REGISTER_VP_INDEX
#define HV_X64_MSR_EOM HV_REGISTER_EOM
+#define HV_X64_MSR_SIRBP HV_REGISTER_SIRBP
#define HV_X64_MSR_SINT0 HV_REGISTER_SINT0
#define HV_X64_MSR_SINT15 HV_REGISTER_SINT15
#define HV_X64_MSR_CRASH_P0 HV_REGISTER_CRASH_P0
diff --git a/drivers/hv/hv_synic.c b/drivers/hv/hv_synic.c
index 9800ae6693a9..a2f712acca82 100644
--- a/drivers/hv/hv_synic.c
+++ b/drivers/hv/hv_synic.c
@@ -19,8 +19,8 @@

void mshv_isr(void)
{
- struct hv_message_page **msg_page =
- this_cpu_ptr(mshv.synic_message_page);
+ struct hv_synic_pages *spages = this_cpu_ptr(mshv.synic_pages);
+ struct hv_message_page **msg_page = &spages->synic_message_page;
struct hv_message *msg;
u32 message_type;
struct mshv_partition *partition;
@@ -115,10 +115,16 @@ void mshv_isr(void)
int mshv_synic_init(unsigned int cpu)
{
union hv_synic_simp simp;
+ union hv_synic_siefp siefp;
+ union hv_synic_sirbp sirbp;
union hv_synic_sint sint;
union hv_synic_scontrol sctrl;
- struct hv_message_page **msg_page =
- this_cpu_ptr(mshv.synic_message_page);
+ struct hv_synic_pages *spages = this_cpu_ptr(mshv.synic_pages);
+ struct hv_message_page **msg_page = &spages->synic_message_page;
+ struct hv_synic_event_flags_page **event_flags_page =
+ &spages->synic_event_flags_page;
+ struct hv_synic_event_ring_page **event_ring_page =
+ &spages->synic_event_ring_page;

/* Setup the Synic's message page */
simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
@@ -127,11 +133,35 @@ int mshv_synic_init(unsigned int cpu)
HV_HYP_PAGE_SIZE,
MEMREMAP_WB);
if (!(*msg_page)) {
- pr_err("%s: memremap failed\n", __func__);
+ pr_err("%s: SIMP memremap failed\n", __func__);
return -EFAULT;
}
hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);

+ /* Setup the Synic's event flags page */
+ siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
+ siefp.siefp_enabled = true;
+ *event_flags_page = memremap(siefp.base_siefp_gpa << PAGE_SHIFT,
+ PAGE_SIZE, MEMREMAP_WB);
+
+ if (!(*event_flags_page)) {
+ pr_err("%s: SIEFP memremap failed\n", __func__);
+ goto cleanup;
+ }
+ hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
+
+ /* Setup the Synic's event ring page */
+ sirbp.as_uint64 = hv_get_register(HV_REGISTER_SIRBP);
+ sirbp.sirbp_enabled = true;
+ *event_ring_page = memremap(sirbp.base_sirbp_gpa << PAGE_SHIFT,
+ PAGE_SIZE, MEMREMAP_WB);
+
+ if (!(*event_ring_page)) {
+ pr_err("%s: SIRBP memremap failed\n", __func__);
+ goto cleanup;
+ }
+ hv_set_register(HV_REGISTER_SIRBP, sirbp.as_uint64);
+
/* Enable intercepts */
sint.as_uint64 = 0;
sint.vector = HYPERVISOR_CALLBACK_VECTOR;
@@ -150,15 +180,40 @@ int mshv_synic_init(unsigned int cpu)
hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64);

return 0;
+
+cleanup:
+ if (*event_ring_page) {
+ sirbp.sirbp_enabled = false;
+ hv_set_register(HV_REGISTER_SIRBP, sirbp.as_uint64);
+ memunmap(*event_ring_page);
+ }
+ if (*event_flags_page) {
+ siefp.siefp_enabled = false;
+ hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
+ memunmap(*event_flags_page);
+ }
+ if (*msg_page) {
+ simp.simp_enabled = false;
+ hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);
+ memunmap(*msg_page);
+ }
+
+ return -EFAULT;
}

int mshv_synic_cleanup(unsigned int cpu)
{
union hv_synic_sint sint;
union hv_synic_simp simp;
+ union hv_synic_siefp siefp;
+ union hv_synic_sirbp sirbp;
union hv_synic_scontrol sctrl;
- struct hv_message_page **msg_page =
- this_cpu_ptr(mshv.synic_message_page);
+ struct hv_synic_pages *spages = this_cpu_ptr(mshv.synic_pages);
+ struct hv_message_page **msg_page = &spages->synic_message_page;
+ struct hv_synic_event_flags_page **event_flags_page =
+ &spages->synic_event_flags_page;
+ struct hv_synic_event_ring_page **event_ring_page =
+ &spages->synic_event_ring_page;

/* Disable the interrupt */
sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 + HV_SYNIC_INTERCEPTION_SINT_INDEX);
@@ -166,6 +221,18 @@ int mshv_synic_cleanup(unsigned int cpu)
hv_set_register(HV_REGISTER_SINT0 + HV_SYNIC_INTERCEPTION_SINT_INDEX,
sint.as_uint64);

+ /* Disable Synic's event ring page */
+ sirbp.as_uint64 = hv_get_register(HV_REGISTER_SIRBP);
+ sirbp.sirbp_enabled = false;
+ hv_set_register(HV_REGISTER_SIRBP, sirbp.as_uint64);
+ memunmap(*event_ring_page);
+
+ /* Disable Synic's event flags page */
+ siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
+ siefp.siefp_enabled = false;
+ hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
+ memunmap(*event_flags_page);
+
/* Disable Synic's message page */
simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
simp.simp_enabled = false;
diff --git a/drivers/hv/mshv_main.c b/drivers/hv/mshv_main.c
index fe6fb2668d36..2adae676dba5 100644
--- a/drivers/hv/mshv_main.c
+++ b/drivers/hv/mshv_main.c
@@ -1118,8 +1118,8 @@ __init mshv_init(void)
return ret;
}

- mshv.synic_message_page = alloc_percpu(struct hv_message_page *);
- if (!mshv.synic_message_page) {
+ mshv.synic_pages = alloc_percpu(struct hv_synic_pages);
+ if (!mshv.synic_pages) {
pr_err("%s: failed to allocate percpu synic page\n", __func__);
misc_deregister(&mshv_dev);
return -ENOMEM;
@@ -1144,7 +1144,7 @@ static void
__exit mshv_exit(void)
{
cpuhp_remove_state(mshv_cpuhp_online);
- free_percpu(mshv.synic_message_page);
+ free_percpu(mshv.synic_pages);

misc_deregister(&mshv_dev);
}
diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
index 8f08d0e9163d..f70391a3320f 100644
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h
@@ -279,8 +279,23 @@ struct hv_timer_message_payload {
__u64 delivery_time; /* When the message was delivered */
} __packed;

+/* Define the synthentic interrupt controller event ring format */
+#define HV_SYNIC_EVENT_RING_MESSAGE_COUNT 63
+
+struct hv_synic_event_ring {
+ u8 signal_masked;
+ u8 ring_full;
+ u16 reserved_z;
+ u32 data[HV_SYNIC_EVENT_RING_MESSAGE_COUNT];
+} __packed;
+
+struct hv_synic_event_ring_page {
+ volatile struct hv_synic_event_ring sint_event_ring[HV_SYNIC_SINT_COUNT];
+};
+
/* Define synthetic interrupt controller flag constants. */
#define HV_EVENT_FLAGS_COUNT (256 * 8)
+#define HV_EVENT_FLAGS_BYTE_COUNT (256)
#define HV_EVENT_FLAGS_LONG_COUNT (256 / sizeof(unsigned long))

/*
@@ -304,9 +319,14 @@ union hv_stimer_config {

/* Define the synthetic interrupt controller event flags format. */
union hv_synic_event_flags {
+ unsigned char flags8[HV_EVENT_FLAGS_BYTE_COUNT];
unsigned long flags[HV_EVENT_FLAGS_LONG_COUNT];
};

+struct hv_synic_event_flags_page {
+ volatile union hv_synic_event_flags event_flags[HV_SYNIC_SINT_COUNT];
+};
+
/* Define SynIC control register. */
union hv_synic_scontrol {
u64 as_uint64;
@@ -349,6 +369,15 @@ union hv_synic_siefp {
} __packed;
};

+union hv_synic_sirbp {
+ u64 as_uint64;
+ struct {
+ u64 sirbp_enabled:1;
+ u64 preserved:11;
+ u64 base_sirbp_gpa:52;
+ } __packed;
+};
+
struct hv_vpset {
u64 format;
u64 valid_bank_mask;
diff --git a/include/linux/mshv.h b/include/linux/mshv.h
index 33f4d0cfee11..679aa3fa8cdb 100644
--- a/include/linux/mshv.h
+++ b/include/linux/mshv.h
@@ -49,8 +49,14 @@ struct mshv_partition {
} vps;
};

+struct hv_synic_pages {
+ struct hv_message_page *synic_message_page;
+ struct hv_synic_event_flags_page *synic_event_flags_page;
+ struct hv_synic_event_ring_page *synic_event_ring_page;
+};
+
struct mshv {
- struct hv_message_page __percpu **synic_message_page;
+ struct hv_synic_pages __percpu *synic_pages;
struct {
spinlock_t lock;
u64 count;
--
2.25.1

Next message: Vineeth Pillai: "[PATCH 07/17] hyperv: Configure SINT for Doorbell"
Previous message: Vineeth Pillai: "[PATCH 06/17] mshv: SynIC port and connection hypercalls"
In reply to: Vineeth Pillai: "[PATCH 06/17] mshv: SynIC port and connection hypercalls"
Next in thread: Vineeth Pillai: "[PATCH 07/17] hyperv: Configure SINT for Doorbell"
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