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Subject[Resend PATCH V5 2/10] x86/hyper-v: Add HvFlushGuestAddressList hypercall support
Date
From: Lan Tianyu <Tianyu.Lan@microsoft.com>

Hyper-V provides HvFlushGuestAddressList() hypercall to flush EPT tlb
with specified ranges. This patch is to add the hypercall support.

Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
---
Change sincd v4:
- Expose function hyperv_fill_flush_guest_mapping_list()
out of hyperv file
- Adjust parameter of hyperv_flush_guest_mapping_range()

Change since v2:
Fix some coding style issues
- Move HV_MAX_FLUSH_PAGES and HV_MAX_FLUSH_REP_COUNT to
hyperv-tlfs.h.
- Calculate HV_MAX_FLUSH_REP_COUNT in the macro definition
- Use HV_MAX_FLUSH_REP_COUNT to define length of gpa_list in
struct hv_guest_mapping_flush_list.

Change since v1:
Add hyperv tlb flush struct to avoid use kvm tlb flush struct
in the hyperv file.
---
arch/x86/hyperv/nested.c | 79 ++++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/hyperv-tlfs.h | 32 +++++++++++++++
arch/x86/include/asm/mshyperv.h | 15 ++++++++
3 files changed, 126 insertions(+)

diff --git a/arch/x86/hyperv/nested.c b/arch/x86/hyperv/nested.c
index b8e60cc50461..3d0f31e46954 100644
--- a/arch/x86/hyperv/nested.c
+++ b/arch/x86/hyperv/nested.c
@@ -7,6 +7,7 @@
*
* Author : Lan Tianyu <Tianyu.Lan@microsoft.com>
*/
+#define pr_fmt(fmt) "Hyper-V: " fmt


#include <linux/types.h>
@@ -54,3 +55,81 @@ int hyperv_flush_guest_mapping(u64 as)
return ret;
}
EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping);
+
+int hyperv_fill_flush_guest_mapping_list(
+ struct hv_guest_mapping_flush_list *flush,
+ u64 start_gfn, u64 pages)
+{
+ u64 cur = start_gfn;
+ u64 additional_pages;
+ int gpa_n = 0;
+
+ do {
+ /*
+ * If flush requests exceed max flush count, go back to
+ * flush tlbs without range.
+ */
+ if (gpa_n >= HV_MAX_FLUSH_REP_COUNT)
+ return -ENOSPC;
+
+ additional_pages = min_t(u64, pages, HV_MAX_FLUSH_PAGES) - 1;
+
+ flush->gpa_list[gpa_n].page.additional_pages = additional_pages;
+ flush->gpa_list[gpa_n].page.largepage = false;
+ flush->gpa_list[gpa_n].page.basepfn = cur;
+
+ pages -= additional_pages + 1;
+ cur += additional_pages + 1;
+ gpa_n++;
+ } while (pages > 0);
+
+ return gpa_n;
+}
+EXPORT_SYMBOL_GPL(hyperv_fill_flush_guest_mapping_list);
+
+int hyperv_flush_guest_mapping_range(u64 as,
+ hyperv_fill_flush_list_func fill_flush_list_func, void *data)
+{
+ struct hv_guest_mapping_flush_list **flush_pcpu;
+ struct hv_guest_mapping_flush_list *flush;
+ u64 status = 0;
+ unsigned long flags;
+ int ret = -ENOTSUPP;
+ int gpa_n = 0;
+
+ if (!hv_hypercall_pg || !fill_flush_list_func)
+ goto fault;
+
+ local_irq_save(flags);
+
+ flush_pcpu = (struct hv_guest_mapping_flush_list **)
+ this_cpu_ptr(hyperv_pcpu_input_arg);
+
+ flush = *flush_pcpu;
+ if (unlikely(!flush)) {
+ local_irq_restore(flags);
+ goto fault;
+ }
+
+ flush->address_space = as;
+ flush->flags = 0;
+
+ gpa_n = fill_flush_list_func(flush, data);
+ if (gpa_n < 0) {
+ local_irq_restore(flags);
+ goto fault;
+ }
+
+ status = hv_do_rep_hypercall(HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST,
+ gpa_n, 0, flush, NULL);
+
+ local_irq_restore(flags);
+
+ if (!(status & HV_HYPERCALL_RESULT_MASK))
+ ret = 0;
+ else
+ ret = status;
+fault:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping_range);
diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index 4139f7650fe5..405a378e1c62 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -10,6 +10,7 @@
#define _ASM_X86_HYPERV_TLFS_H

#include <linux/types.h>
+#include <asm/page.h>

/*
* The below CPUID leaves are present if VersionAndFeatures.HypervisorPresent
@@ -358,6 +359,7 @@ struct hv_tsc_emulation_status {
#define HVCALL_POST_MESSAGE 0x005c
#define HVCALL_SIGNAL_EVENT 0x005d
#define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE 0x00af
+#define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST 0x00b0

#define HV_X64_MSR_VP_ASSIST_PAGE_ENABLE 0x00000001
#define HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT 12
@@ -757,6 +759,36 @@ struct hv_guest_mapping_flush {
u64 flags;
};

+/*
+ * HV_MAX_FLUSH_PAGES = "additional_pages" + 1. It's limited
+ * by the bitwidth of "additional_pages" in union hv_gpa_page_range.
+ */
+#define HV_MAX_FLUSH_PAGES (2048)
+
+/* HvFlushGuestPhysicalAddressList hypercall */
+union hv_gpa_page_range {
+ u64 address_space;
+ struct {
+ u64 additional_pages:11;
+ u64 largepage:1;
+ u64 basepfn:52;
+ } page;
+};
+
+/*
+ * All input flush parameters should be in single page. The max flush
+ * count is equal with how many entries of union hv_gpa_page_range can
+ * be populated into the input parameter page.
+ */
+#define HV_MAX_FLUSH_REP_COUNT (PAGE_SIZE - 2 * sizeof(u64) / \
+ sizeof(union hv_gpa_page_range))
+
+struct hv_guest_mapping_flush_list {
+ u64 address_space;
+ u64 flags;
+ union hv_gpa_page_range gpa_list[HV_MAX_FLUSH_REP_COUNT];
+};
+
/* HvFlushVirtualAddressSpace, HvFlushVirtualAddressList hypercalls */
struct hv_tlb_flush {
u64 address_space;
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 1d0a7778e163..7da712f65398 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -22,6 +22,11 @@ struct ms_hyperv_info {

extern struct ms_hyperv_info ms_hyperv;

+
+typedef int (*hyperv_fill_flush_list_func)(
+ struct hv_guest_mapping_flush_list *flush,
+ void *data);
+
/*
* Generate the guest ID.
*/
@@ -348,6 +353,11 @@ void set_hv_tscchange_cb(void (*cb)(void));
void clear_hv_tscchange_cb(void);
void hyperv_stop_tsc_emulation(void);
int hyperv_flush_guest_mapping(u64 as);
+int hyperv_flush_guest_mapping_range(u64 as,
+ hyperv_fill_flush_list_func fill_func, void *data);
+int hyperv_fill_flush_guest_mapping_list(
+ struct hv_guest_mapping_flush_list *flush,
+ u64 start_gfn, u64 end_gfn);

#ifdef CONFIG_X86_64
void hv_apic_init(void);
@@ -370,6 +380,11 @@ static inline struct hv_vp_assist_page *hv_get_vp_assist_page(unsigned int cpu)
return NULL;
}
static inline int hyperv_flush_guest_mapping(u64 as) { return -1; }
+static inline int hyperv_flush_guest_mapping_range(u64 as,
+ hyperv_fill_flush_list_func fill_func, void *data);
+{
+ return -1;
+}
#endif /* CONFIG_HYPERV */

#ifdef CONFIG_HYPERV_TSCPAGE
--
2.14.4
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