Drivers: hv: balloon: Support status report for larger page sizes

DM_STATUS_REPORT expects the numbers of pages in the unit of 4k pages
(HV_HYP_PAGE) instead of guest pages, so to make it work when guest page
sizes are larger than 4k, convert the numbers of guest pages into the
numbers of HV_HYP_PAGEs.

Note that the numbers of guest pages are still used for tracing because
tracing is internal to the guest kernel.

Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220325023212.1570049-2-boqun.feng@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index f2d05bff424530d7ba28c6ac65e2874e0cc70907..062156b88a876415142f96112e78e8c8d04d3274 100644 (file)
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -17,6 +17,7 @@
 #include <linux/slab.h>
 #include <linux/kthread.h>
 #include <linux/completion.h>
+#include <linux/count_zeros.h>
 #include <linux/memory_hotplug.h>
 #include <linux/memory.h>
 #include <linux/notifier.h>
@@ -1130,6 +1131,7 @@ static void post_status(struct hv_dynmem_device *dm)
        struct dm_status status;
        unsigned long now = jiffies;
        unsigned long last_post = last_post_time;
+       unsigned long num_pages_avail, num_pages_committed;
 
        if (pressure_report_delay > 0) {
                --pressure_report_delay;
@@ -1154,16 +1156,21 @@ static void post_status(struct hv_dynmem_device *dm)
         * num_pages_onlined) as committed to the host, otherwise it can try
         * asking us to balloon them out.
         */
-       status.num_avail = si_mem_available();
-       status.num_committed = vm_memory_committed() +
+       num_pages_avail = si_mem_available();
+       num_pages_committed = vm_memory_committed() +
                dm->num_pages_ballooned +
                (dm->num_pages_added > dm->num_pages_onlined ?
                 dm->num_pages_added - dm->num_pages_onlined : 0) +
                compute_balloon_floor();
 
-       trace_balloon_status(status.num_avail, status.num_committed,
+       trace_balloon_status(num_pages_avail, num_pages_committed,
                             vm_memory_committed(), dm->num_pages_ballooned,
                             dm->num_pages_added, dm->num_pages_onlined);
+
+       /* Convert numbers of pages into numbers of HV_HYP_PAGEs. */
+       status.num_avail = num_pages_avail * NR_HV_HYP_PAGES_IN_PAGE;
+       status.num_committed = num_pages_committed * NR_HV_HYP_PAGES_IN_PAGE;
+
        /*
         * If our transaction ID is no longer current, just don't
         * send the status. This can happen if we were interrupted