RE: [PATCH V2 10/13] x86/hyper-v: Add HvFlushGuestAddressList hypercall support
From: Tianyu Lan Sent: Monday, September 17, 2018 8:19 PM
>
> #include
> #include
> #include
> #include
> +#include
Hopefully asm/kvm_host.h does not need to be #included, given
the new code structure.
>
> #include
>
> +/*
> + * 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)
> +
I would recommend putting the above two definitions in
hyperv-tlfs.h. They are directly tied to the data structures defined
by Hyper-V in the TLFS. Put MAX_FLUSH_PAGES immediately after
the definition for hv_gpa_page_range so that the dependency is
obvious.
For MAX_FLUSH_REP_COUNT, can you do the calculation in
the #define rather than just in the comment? Alternatively, define
the gpa_list[] array to be of MAX_FLUSH_REP_COUNT size, and then
add a compile time assert that the size of struct
hv_guest_mapping_flush_list is exactly one page in size. It's just
a good way to use the compiler to help check for mistakes.
Also prefix them both with HV_ since they will be more
globally visible as part of hyperv-tlfs.h.
> int hyperv_flush_guest_mapping(u64 as)
> {
> struct hv_guest_mapping_flush **flush_pcpu;
> @@ -54,3 +71,89 @@ int hyperv_flush_guest_mapping(u64 as)
> return ret;
> }
> EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping);
> +
> +static int fill_flush_list(union hv_gpa_page_range gpa_list[],
> + int offset, u64 start_gfn, u64 pages)
> +{
> + int gpa_n = offset;
> + u64 cur = start_gfn;
> + u64 additional_pages;
> +
> + do {
> + if (gpa_n >= MAX_FLUSH_REP_COUNT) {
> + pr_warn("Request exceeds HvFlushGuestList max flush
> count.");
> + return -ENOSPC;
I wonder if the warning is really needed. When the error is returned up
through the higher levels of code, won't the higher levels just fallback to
the non-enlightened flush code? So nothing is actually goes wrong; it's just
that a slower code path gets taken. A comment about such expectations
might be helpful.
> + }
> +
> + if (pages > MAX_FLUSH_PAGES) {
> + additional_pages = MAX_FLUSH_PAGES - 1;
> + pages -= MAX_FLUSH_PAGES;
> + } else {
> + additional_pages = pages - 1;
> + pages = 0;
> + }
The above code is really doing:
additional_pages = min(pages, MAX_FLUSH_PAGES) - 1;
pages -= additional_pages + 1;
And you might want to move the decrement of 'pages' down to the
bottom of the loop where you update the other loop variables.
> +
> + 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 hyperv_tlb_range *range)
> +{
> + 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->pages);
> + else if (range->parse_flush_list_func)
> + gpa_n = range->parse_flush_list_func(flush->gpa_list, gpa_n,
> + range->flush_list, fill_flush_list);
> + else
> + gpa_n = -1;
> +
> + 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_r
[PATCH V2 10/13] x86/hyper-v: Add HvFlushGuestAddressList hypercall support
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
---
Change since v1:
Add hyperv tlb flush struct to avoid use kvm tlb flush struct
in the hyperv file.
---
arch/x86/hyperv/nested.c | 103 +
arch/x86/include/asm/hyperv-tlfs.h | 17 ++
arch/x86/include/asm/mshyperv.h| 16 ++
3 files changed, 136 insertions(+)
diff --git a/arch/x86/hyperv/nested.c b/arch/x86/hyperv/nested.c
index b8e60cc50461..40ddbfd54573 100644
--- a/arch/x86/hyperv/nested.c
+++ b/arch/x86/hyperv/nested.c
@@ -7,15 +7,32 @@
*
* Author : Lan Tianyu
*/
+#define pr_fmt(fmt) "Hyper-V: " fmt
#include
#include
#include
#include
+#include
#include
+/*
+ * 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 +71,89 @@ int hyperv_flush_guest_mapping(u64 as)
return ret;
}
EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping);
+
+static int fill_flush_list(union hv_gpa_page_range gpa_list[],
+ int offset, u64 start_gfn, u64 pages)
+{
+ int gpa_n = offset;
+ u64 cur = start_gfn;
+ u64 additional_pages;
+
+ do {
+ if (gpa_n >= MAX_FLUSH_REP_COUNT) {
+ pr_warn("Request exceeds HvFlushGuestList max flush
count.");
+ 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 hyperv_tlb_range *range)
+{
+ 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->pages);
+ else if (range->parse_flush_list_func)
+ gpa_n = range->parse_flush_list_func(flush->gpa_list, gpa_n,
+ range->flush_list, fill_flush_list);
+ else
+ gpa_n = -1;
+
+ 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 e977b6b3a538..512f22b4 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_MESSAGE0x005c
#define HVCALL_SIGNAL_EVENT0x005d
#define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE 0x00af
+#define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST 0x00b0
#define HV_X64_MSR_VP_ASSIST_PAGE_ENABLE 0x0001
#define HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT12
@@ -750,6 +751,22 @@ struct hv_guest_mapping_flush {
u64 flags;
};
+/* HvFlushGuestPhysicalAddressList hypercall */
+union hv_gpa_page_range {
+ u64 address_space;
+ struct {
+
