From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: KVM <kvm@vger.kernel.org>, Janosch Frank <frankja@linux.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
David Hildenbrand <david@redhat.com>,
linux-s390 <linux-s390@vger.kernel.org>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>
Subject: [GIT PULL 16/17] KVM: s390: pv: properly handle page flags for protected guests
Date: Sun, 31 Oct 2021 13:11:03 +0100 [thread overview]
Message-ID: <20211031121104.14764-17-borntraeger@de.ibm.com> (raw)
In-Reply-To: <20211031121104.14764-1-borntraeger@de.ibm.com>
From: Claudio Imbrenda <imbrenda@linux.ibm.com>
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>
---
arch/s390/include/asm/pgtable.h | 9 ++++++---
arch/s390/include/asm/uv.h | 10 ++++++++--
arch/s390/kernel/uv.c | 34 ++++++++++++++++++++++++++++++++-
arch/s390/mm/gmap.c | 4 +++-
4 files changed, 50 insertions(+), 7 deletions(-)
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index b61426c9ef17..e43416950245 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1074,8 +1074,9 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
pte_t res;
res = ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID));
+ /* At this point the reference through the mapping is still present */
if (mm_is_protected(mm) && pte_present(res))
- uv_convert_from_secure(pte_val(res) & PAGE_MASK);
+ uv_convert_owned_from_secure(pte_val(res) & PAGE_MASK);
return res;
}
@@ -1091,8 +1092,9 @@ static inline pte_t ptep_clear_flush(struct vm_area_struct *vma,
pte_t res;
res = ptep_xchg_direct(vma->vm_mm, addr, ptep, __pte(_PAGE_INVALID));
+ /* At this point the reference through the mapping is still present */
if (mm_is_protected(vma->vm_mm) && pte_present(res))
- uv_convert_from_secure(pte_val(res) & PAGE_MASK);
+ uv_convert_owned_from_secure(pte_val(res) & PAGE_MASK);
return res;
}
@@ -1116,8 +1118,9 @@ static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
} else {
res = ptep_xchg_lazy(mm, addr, ptep, __pte(_PAGE_INVALID));
}
+ /* At this point the reference through the mapping is still present */
if (mm_is_protected(mm) && pte_present(res))
- uv_convert_from_secure(pte_val(res) & PAGE_MASK);
+ uv_convert_owned_from_secure(pte_val(res) & PAGE_MASK);
return res;
}
diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
index 9ab1914c5b95..72d3e49c2860 100644
--- a/arch/s390/include/asm/uv.h
+++ b/arch/s390/include/asm/uv.h
@@ -356,8 +356,9 @@ static inline int is_prot_virt_host(void)
}
int gmap_make_secure(struct gmap *gmap, unsigned long gaddr, void *uvcb);
-int uv_destroy_page(unsigned long paddr);
+int uv_destroy_owned_page(unsigned long paddr);
int uv_convert_from_secure(unsigned long paddr);
+int uv_convert_owned_from_secure(unsigned long paddr);
int gmap_convert_to_secure(struct gmap *gmap, unsigned long gaddr);
void setup_uv(void);
@@ -365,7 +366,7 @@ void setup_uv(void);
#define is_prot_virt_host() 0
static inline void setup_uv(void) {}
-static inline int uv_destroy_page(unsigned long paddr)
+static inline int uv_destroy_owned_page(unsigned long paddr)
{
return 0;
}
@@ -374,6 +375,11 @@ static inline int uv_convert_from_secure(unsigned long paddr)
{
return 0;
}
+
+static inline int uv_convert_owned_from_secure(unsigned long paddr)
+{
+ return 0;
+}
#endif
#endif /* _ASM_S390_UV_H */
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,
@@ -120,6 +120,22 @@ int uv_destroy_page(unsigned long paddr)
return 0;
}
+/*
+ * 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).
@@ -139,6 +155,22 @@ int uv_convert_from_secure(unsigned long paddr)
return 0;
}
+/*
+ * 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
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index d63c0ccc5ccd..dfee0ebb2fac 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -2684,8 +2684,10 @@ static int __s390_reset_acc(pte_t *ptep, unsigned long addr,
{
pte_t pte = READ_ONCE(*ptep);
+ /* There is a reference through the mapping */
if (pte_present(pte))
- WARN_ON_ONCE(uv_destroy_page(pte_val(pte) & PAGE_MASK));
+ WARN_ON_ONCE(uv_destroy_owned_page(pte_val(pte) & PAGE_MASK));
+
return 0;
}
--
2.31.1
next prev parent reply other threads:[~2021-10-31 12:11 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-31 12:10 [GIT PULL 00/17] KVM: s390: Fixes and Features for 5.16 Christian Borntraeger
2021-10-31 12:10 ` [GIT PULL 01/17] s390/gmap: validate VMA in __gmap_zap() Christian Borntraeger
2021-10-31 12:10 ` [GIT PULL 02/17] s390/gmap: don't unconditionally call pte_unmap_unlock() " Christian Borntraeger
2021-10-31 12:10 ` [GIT PULL 03/17] s390/mm: validate VMA in PGSTE manipulation functions Christian Borntraeger
2021-10-31 12:10 ` [GIT PULL 04/17] s390/mm: fix VMA and page table handling code in storage key handling functions Christian Borntraeger
2021-10-31 12:10 ` [GIT PULL 05/17] s390/uv: fully validate the VMA before calling follow_page() Christian Borntraeger
2021-10-31 12:10 ` [GIT PULL 06/17] s390/mm: no need for pte_alloc_map_lock() if we know the pmd is present Christian Borntraeger
2021-10-31 12:10 ` [GIT PULL 07/17] s390/mm: optimize set_guest_storage_key() Christian Borntraeger
2021-10-31 12:10 ` [GIT PULL 08/17] s390/mm: optimize reset_guest_reference_bit() Christian Borntraeger
2021-10-31 12:10 ` [GIT PULL 09/17] KVM: s390: pv: add macros for UVC CC values Christian Borntraeger
2021-10-31 12:10 ` [GIT PULL 10/17] KVM: s390: pv: avoid double free of sida page Christian Borntraeger
2021-10-31 12:10 ` [GIT PULL 11/17] KVM: s390: pv: avoid stalls for kvm_s390_pv_init_vm Christian Borntraeger
2021-10-31 12:10 ` [GIT PULL 12/17] KVM: s390: pv: avoid stalls when making pages secure Christian Borntraeger
2021-10-31 12:11 ` [GIT PULL 13/17] KVM: s390: Simplify SIGP Set Arch handling Christian Borntraeger
2021-10-31 12:11 ` [GIT PULL 14/17] KVM: s390: Add a routine for setting userspace CPU state Christian Borntraeger
2021-10-31 12:11 ` [GIT PULL 15/17] KVM: s390: Fix handle_sske page fault handling Christian Borntraeger
2021-10-31 12:11 ` Christian Borntraeger [this message]
2021-10-31 12:11 ` [GIT PULL 17/17] KVM: s390: add debug statement for diag 318 CPNC data Christian Borntraeger
2021-11-01 7:35 ` [GIT PULL 00/17] KVM: s390: Fixes and Features for 5.16 Paolo Bonzini
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