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Subject[PATCH 10/13] x86/hyper-v: Add HvFlushGuestAddressList hypercall support
Date
Hyper-V provides HvFlushGuestAddressList() hypercall to flush EPT tlb
with specified ranges. This patch is to add the hypercall support.

Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
---
arch/x86/hyperv/nested.c | 110 +++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/hyperv-tlfs.h | 17 ++++++
arch/x86/include/asm/mshyperv.h | 8 +++
3 files changed, 135 insertions(+)

diff --git a/arch/x86/hyperv/nested.c b/arch/x86/hyperv/nested.c
index b8e60cc50461..bb716ed94320 100644
--- a/arch/x86/hyperv/nested.c
+++ b/arch/x86/hyperv/nested.c
@@ -7,15 +7,32 @@
*
* Author : Lan Tianyu <Tianyu.Lan@microsoft.com>
*/
+#define pr_fmt(fmt) "Hyper-V: " fmt


#include <linux/types.h>
#include <asm/hyperv-tlfs.h>
#include <asm/mshyperv.h>
#include <asm/tlbflush.h>
+#include <asm/kvm_host.h>

#include <asm/trace/hyperv.h>

+/*
+ * MAX_FLUSH_PAGES = "additional_pages" + 1. It's limited
+ * by the bitwidth of "additional_pages" in union hv_gpa_page_range.
+ */
+#define MAX_FLUSH_PAGES (2048)
+
+/*
+ * All input flush parameters are in single page. The max flush count
+ * is equal with how many entries of union hv_gpa_page_range can be
+ * populated in the input parameter page. MAX_FLUSH_REP_COUNT
+ * = (4096 - 16) / 8. (“Page Size” - "Address Space" - "Flags") /
+ * "GPA Range".
+ */
+#define MAX_FLUSH_REP_COUNT (510)
+
int hyperv_flush_guest_mapping(u64 as)
{
struct hv_guest_mapping_flush **flush_pcpu;
@@ -54,3 +71,96 @@ int hyperv_flush_guest_mapping(u64 as)
return ret;
}
EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping);
+
+static inline int fill_flush_list(union hv_gpa_page_range gpa_list[],
+ int offset, u64 start_gfn, u64 end_gfn)
+{
+ int gpa_n = offset;
+ u64 cur = start_gfn;
+ u64 pages = end_gfn - start_gfn + 1;
+ u64 additional_pages;
+
+ if (end_gfn < start_gfn)
+ return -EINVAL;
+
+ do {
+ if (gpa_n == MAX_FLUSH_REP_COUNT) {
+ pr_warn("Request exceeds HvFlushGuestList max flush count.\n");
+ return -ENOSPC;
+ }
+
+ if (pages > MAX_FLUSH_PAGES) {
+ additional_pages = MAX_FLUSH_PAGES - 1;
+ pages -= MAX_FLUSH_PAGES;
+ } else {
+ additional_pages = pages - 1;
+ pages = 0;
+ }
+
+ gpa_list[gpa_n].page.additional_pages = additional_pages;
+ gpa_list[gpa_n].page.largepage = false;
+ gpa_list[gpa_n].page.basepfn = cur;
+
+ cur += additional_pages + 1;
+ gpa_n++;
+ } while (pages > 0);
+
+ return gpa_n;
+}
+
+int hyperv_flush_guest_mapping_range(u64 as, struct kvm_tlb_range *range)
+{
+ struct kvm_mmu_page *sp;
+ 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)
+ 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;
+
+ if (!range->flush_list) {
+ gpa_n = fill_flush_list(flush->gpa_list, gpa_n,
+ range->start_gfn, range->end_gfn);
+ } else {
+ list_for_each_entry(sp, range->flush_list,
+ flush_link) {
+ u64 end_gfn = sp->gfn +
+ KVM_PAGES_PER_HPAGE(sp->role.level) - 1;
+ gpa_n = fill_flush_list(flush->gpa_list, gpa_n,
+ sp->gfn, end_gfn);
+ }
+ }
+
+ 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;
+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 e977b6b3a538..512f22b49999 100644
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -353,6 +353,7 @@ 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
@@ -750,6 +751,22 @@ struct hv_guest_mapping_flush {
u64 flags;
};

+/* HvFlushGuestPhysicalAddressList hypercall */
+union hv_gpa_page_range {
+ u64 address_space;
+ struct {
+ u64 additional_pages:11;
+ u64 largepage:1;
+ u64 basepfn:52;
+ } page;
+};
+
+struct hv_guest_mapping_flush_list {
+ u64 address_space;
+ u64 flags;
+ union hv_gpa_page_range gpa_list[];
+};
+
/* 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 f37704497d8f..da68574404bf 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -22,6 +22,8 @@ struct ms_hyperv_info {

extern struct ms_hyperv_info ms_hyperv;

+struct kvm_tlb_range;
+
/*
* Generate the guest ID.
*/
@@ -348,6 +350,7 @@ 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, struct kvm_tlb_range *range);

#ifdef CONFIG_X86_64
void hv_apic_init(void);
@@ -368,6 +371,11 @@ 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,
+ struct kvm_tlb_range *range)
+{
+ return -1;
+}
#endif /* CONFIG_HYPERV */

#ifdef CONFIG_HYPERV_TSCPAGE
--
2.14.4
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