From: Claudio Imbrenda <imbrenda@linux.ibm.com> To: kvm@vger.kernel.org Cc: cohuck@redhat.com, borntraeger@de.ibm.com, frankja@linux.ibm.com, thuth@redhat.com, pasic@linux.ibm.com, david@redhat.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 03/13] KVM: s390: pv: properly handle page flags for protected guests Date: Wed, 28 Jul 2021 16:26:21 +0200 [thread overview] Message-ID: <20210728142631.41860-4-imbrenda@linux.ibm.com> (raw) In-Reply-To: <20210728142631.41860-1-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. 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> --- 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 dcac7b2df72c..0f1af2232ebe 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 12c5f006c136..bbd51aa94d05 100644 --- a/arch/s390/include/asm/uv.h +++ b/arch/s390/include/asm/uv.h @@ -351,8 +351,9 @@ 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); @@ -362,7 +363,7 @@ void adjust_to_uv_max(unsigned long *vmax); static inline void setup_uv(void) {} static inline void adjust_to_uv_max(unsigned long *vmax) {} -static inline int uv_destroy_page(unsigned long paddr) +static inline int uv_destroy_owned_page(unsigned long paddr) { return 0; } @@ -371,6 +372,11 @@ 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 #if defined(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) || IS_ENABLED(CONFIG_KVM) diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c index fd0faa51c1bb..5a6ac965f379 100644 --- a/arch/s390/kernel/uv.c +++ b/arch/s390/kernel/uv.c @@ -115,7 +115,7 @@ 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, @@ -135,6 +135,22 @@ 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). @@ -154,6 +170,22 @@ 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 9bb2c7512cd5..de679facc720 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -2678,8 +2678,10 @@ 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:[~2021-07-28 14:31 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-28 14:26 [PATCH v2 00/13] KVM: s390: pv: implement lazy destroy Claudio Imbrenda 2021-07-28 14:26 ` [PATCH v2 01/13] KVM: s390: pv: avoid stall notifications for some UVCs Claudio Imbrenda 2021-07-29 9:58 ` Janosch Frank 2021-07-29 12:52 ` Claudio Imbrenda 2021-07-29 10:49 ` Cornelia Huck 2021-07-29 13:22 ` Claudio Imbrenda 2021-07-28 14:26 ` [PATCH v2 02/13] KVM: s390: pv: leak the ASCE page when destroy fails Claudio Imbrenda 2021-07-29 10:41 ` Janosch Frank 2021-07-29 12:54 ` Claudio Imbrenda 2021-07-29 13:45 ` Janosch Frank 2021-07-28 14:26 ` Claudio Imbrenda [this message] 2021-07-29 11:43 ` [PATCH v2 03/13] KVM: s390: pv: properly handle page flags for protected guests Janosch Frank 2021-07-28 14:26 ` [PATCH v2 04/13] KVM: s390: pv: handle secure storage violations " Claudio Imbrenda 2021-07-28 14:26 ` [PATCH v2 05/13] KVM: s390: pv: handle secure storage exceptions for normal guests Claudio Imbrenda 2021-07-29 12:17 ` Janosch Frank 2021-07-29 13:28 ` Claudio Imbrenda 2021-07-28 14:26 ` [PATCH v2 06/13] KVM: s390: pv: refactor s390_reset_acc Claudio Imbrenda 2021-07-28 14:26 ` [PATCH v2 07/13] KVM: s390: pv: usage counter instead of flag Claudio Imbrenda 2021-07-28 14:26 ` [PATCH v2 08/13] KVM: s390: pv: add export before import Claudio Imbrenda 2021-07-28 14:26 ` [PATCH v2 09/13] KVM: s390: pv: lazy destroy for reboot Claudio Imbrenda 2021-07-28 14:26 ` [PATCH v2 10/13] KVM: s390: pv: extend lazy destroy to handle shutdown Claudio Imbrenda 2021-07-28 14:26 ` [PATCH v2 11/13] KVM: s390: pv: module parameter to fence lazy destroy Claudio Imbrenda 2021-07-28 14:26 ` [PATCH v2 12/13] KVM: s390: pv: add OOM notifier for " Claudio Imbrenda 2021-07-28 14:26 ` [PATCH v2 13/13] KVM: s390: pv: add support for UV feature bits Claudio Imbrenda 2021-07-29 9:52 ` Janosch Frank 2021-07-29 13:28 ` Claudio Imbrenda
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