summaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/uv.c
diff options
context:
space:
mode:
authorClaudio Imbrenda <imbrenda@linux.ibm.com>2021-09-20 15:24:54 +0200
committerChristian Borntraeger <borntraeger@de.ibm.com>2021-10-27 07:55:53 +0200
commit380d97bd02fca7b9b41aec2d1c767874d602bc78 (patch)
tree8e9f822ec608744ebcb9f4e5ddb293936e59393a /arch/s390/kernel/uv.c
parentKVM: s390: Fix handle_sske page fault handling (diff)
downloadlinux-380d97bd02fca7b9b41aec2d1c767874d602bc78.tar.xz
linux-380d97bd02fca7b9b41aec2d1c767874d602bc78.zip
KVM: s390: pv: properly handle page flags for protected guests
Introduce variants of the convert and destroy page functions that also clear the PG_arch_1 bit used to mark them as secure pages. The PG_arch_1 flag is always allowed to overindicate; using the new functions introduced here allows to reduce the extent of overindication and thus improve performance. These new functions can only be called on pages for which a reference is already being held. Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Link: https://lore.kernel.org/r/20210920132502.36111-7-imbrenda@linux.ibm.com Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/uv.c')
-rw-r--r--arch/s390/kernel/uv.c34
1 files changed, 33 insertions, 1 deletions
diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
index 09b80d371409..8b0e62507d62 100644
--- a/arch/s390/kernel/uv.c
+++ b/arch/s390/kernel/uv.c
@@ -100,7 +100,7 @@ static int uv_pin_shared(unsigned long paddr)
*
* @paddr: Absolute host address of page to be destroyed
*/
-int uv_destroy_page(unsigned long paddr)
+static int uv_destroy_page(unsigned long paddr)
{
struct uv_cb_cfs uvcb = {
.header.cmd = UVC_CMD_DESTR_SEC_STOR,
@@ -121,6 +121,22 @@ int uv_destroy_page(unsigned long paddr)
}
/*
+ * The caller must already hold a reference to the page
+ */
+int uv_destroy_owned_page(unsigned long paddr)
+{
+ struct page *page = phys_to_page(paddr);
+ int rc;
+
+ get_page(page);
+ rc = uv_destroy_page(paddr);
+ if (!rc)
+ clear_bit(PG_arch_1, &page->flags);
+ put_page(page);
+ return rc;
+}
+
+/*
* Requests the Ultravisor to encrypt a guest page and make it
* accessible to the host for paging (export).
*
@@ -140,6 +156,22 @@ int uv_convert_from_secure(unsigned long paddr)
}
/*
+ * The caller must already hold a reference to the page
+ */
+int uv_convert_owned_from_secure(unsigned long paddr)
+{
+ struct page *page = phys_to_page(paddr);
+ int rc;
+
+ get_page(page);
+ rc = uv_convert_from_secure(paddr);
+ if (!rc)
+ clear_bit(PG_arch_1, &page->flags);
+ put_page(page);
+ return rc;
+}
+
+/*
* Calculate the expected ref_count for a page that would otherwise have no
* further pins. This was cribbed from similar functions in other places in
* the kernel, but with some slight modifications. We know that a secure