From: Christian Borntraeger <borntraeger@de.ibm.com>
To: David Hildenbrand <david@redhat.com>,
Janosch Frank <frankja@linux.vnet.ibm.com>
Cc: KVM <kvm@vger.kernel.org>, Cornelia Huck <cohuck@redhat.com>,
Thomas Huth <thuth@redhat.com>,
Ulrich Weigand <Ulrich.Weigand@de.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-s390 <linux-s390@vger.kernel.org>,
Michael Mueller <mimu@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Janosch Frank <frankja@linux.ibm.com>
Subject: Re: [PATCH 06/35] s390/mm: add (non)secure page access exceptions handlers
Date: Fri, 14 Feb 2020 20:59:27 +0100 [thread overview]
Message-ID: <9bbf5e4e-8bdc-b990-f39f-44c6a3f54ba0@de.ibm.com> (raw)
In-Reply-To: <c05f8672-dc29-271a-66d2-73138406cf21@redhat.com>
On 14.02.20 19:05, David Hildenbrand wrote:
> On 07.02.20 12:39, Christian Borntraeger wrote:
>> From: Vasily Gorbik <gor@linux.ibm.com>
>>
>> Add exceptions handlers performing transparent transition of non-secure
>> pages to secure (import) upon guest access and secure pages to
>> non-secure (export) upon hypervisor access.
>>
>> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
>> [frankja@linux.ibm.com: adding checks for failures]
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> [imbrenda@linux.ibm.com: adding a check for gmap fault]
>> Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
>> [borntraeger@de.ibm.com: patch merging, splitting, fixing]
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> ---
>> arch/s390/kernel/pgm_check.S | 4 +-
>> arch/s390/mm/fault.c | 86 ++++++++++++++++++++++++++++++++++++
>> 2 files changed, 88 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/s390/kernel/pgm_check.S b/arch/s390/kernel/pgm_check.S
>> index 59dee9d3bebf..27ac4f324c70 100644
>> --- a/arch/s390/kernel/pgm_check.S
>> +++ b/arch/s390/kernel/pgm_check.S
>> @@ -78,8 +78,8 @@ PGM_CHECK(do_dat_exception) /* 39 */
>> PGM_CHECK(do_dat_exception) /* 3a */
>> PGM_CHECK(do_dat_exception) /* 3b */
>> PGM_CHECK_DEFAULT /* 3c */
>> -PGM_CHECK_DEFAULT /* 3d */
>> -PGM_CHECK_DEFAULT /* 3e */
>> +PGM_CHECK(do_secure_storage_access) /* 3d */
>> +PGM_CHECK(do_non_secure_storage_access) /* 3e */
>> PGM_CHECK_DEFAULT /* 3f */
>> PGM_CHECK_DEFAULT /* 40 */
>> PGM_CHECK_DEFAULT /* 41 */
>> diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
>> index 7b0bb475c166..fab4219fa0be 100644
>> --- a/arch/s390/mm/fault.c
>> +++ b/arch/s390/mm/fault.c
>> @@ -38,6 +38,7 @@
>> #include <asm/irq.h>
>> #include <asm/mmu_context.h>
>> #include <asm/facility.h>
>> +#include <asm/uv.h>
>> #include "../kernel/entry.h"
>>
>> #define __FAIL_ADDR_MASK -4096L
>> @@ -816,3 +817,88 @@ static int __init pfault_irq_init(void)
>> early_initcall(pfault_irq_init);
>>
>> #endif /* CONFIG_PFAULT */
>> +
>> +#if IS_ENABLED(CONFIG_KVM)
>> +void do_secure_storage_access(struct pt_regs *regs)
>> +{
>> + unsigned long addr = regs->int_parm_long & __FAIL_ADDR_MASK;
>> + struct vm_area_struct *vma;
>> + struct mm_struct *mm;
>> + struct page *page;
>> + int rc;
>> +
>> + switch (get_fault_type(regs)) {
>> + case USER_FAULT:
>> + mm = current->mm;
>> + down_read(&mm->mmap_sem);
>> + vma = find_vma(mm, addr);
>> + if (!vma) {
>> + up_read(&mm->mmap_sem);
>> + do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);
>> + break;
>> + }
>> + page = follow_page(vma, addr, FOLL_WRITE | FOLL_GET);
>> + if (IS_ERR_OR_NULL(page)) {
>> + up_read(&mm->mmap_sem);
>> + break;
>> + }
>> + if (arch_make_page_accessible(page))
>> + send_sig(SIGSEGV, current, 0);
>> + put_page(page);
>> + up_read(&mm->mmap_sem);
>> + break;
>> + case KERNEL_FAULT:
>> + page = phys_to_page(addr);
>> + if (unlikely(!try_get_page(page)))
>> + break;
>> + rc = arch_make_page_accessible(page);
>> + put_page(page);
>> + if (rc)
>> + BUG();
>> + break;
>> + case VDSO_FAULT:
>> + /* fallthrough */
>> + case GMAP_FAULT:
>> + /* fallthrough */
>
> Could we ever get here from the SIE?
GMAP_FAULT is only set if we came from the sie critical section, so unless we have a bug no.
>
>> + default:
>> + do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);
>> + WARN_ON_ONCE(1);
>> + }
>> +}
>> +NOKPROBE_SYMBOL(do_secure_storage_access);
>> +
>> +void do_non_secure_storage_access(struct pt_regs *regs)
>> +{
>> + unsigned long gaddr = regs->int_parm_long & __FAIL_ADDR_MASK;
>> + struct gmap *gmap = (struct gmap *)S390_lowcore.gmap;
>> + struct uv_cb_cts uvcb = {
>> + .header.cmd = UVC_CMD_CONV_TO_SEC_STOR,
>> + .header.len = sizeof(uvcb),
>> + .guest_handle = gmap->guest_handle,
>> + .gaddr = gaddr,
>> + };
>> + int rc;
>> +
>> + if (get_fault_type(regs) != GMAP_FAULT) {
>> + do_fault_error(regs, VM_READ | VM_WRITE, VM_FAULT_BADMAP);
>> + WARN_ON_ONCE(1);
>> + return;
>> + }
>> +
>> + rc = uv_make_secure(gmap, gaddr, &uvcb);
>> + if (rc == -EINVAL && uvcb.header.rc != 0x104)
>> + send_sig(SIGSEGV, current, 0);
>
>
> Looks good to me, but I don't feel like being ready for an r-b. I'll
> have to let that sink in :)
>
> Assumed-is-okay-by: David Hildenbrand <david@redhat.com>
>
>
next prev parent reply other threads:[~2020-02-14 19:59 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-07 11:39 [PATCH 00/35] KVM: s390: Add support for protected VMs Christian Borntraeger
2020-02-07 11:39 ` [PATCH 01/35] mm:gup/writeback: add callbacks for inaccessible pages Christian Borntraeger
2020-02-10 17:27 ` Christian Borntraeger
2020-02-11 11:26 ` Will Deacon
2020-02-11 11:43 ` Christian Borntraeger
2020-02-13 14:48 ` Christian Borntraeger
2020-02-18 16:02 ` Will Deacon
2020-02-13 19:56 ` Sean Christopherson
2020-02-13 20:13 ` Christian Borntraeger
2020-02-13 20:46 ` Sean Christopherson
2020-02-17 20:55 ` Tom Lendacky
2020-02-17 21:14 ` Christian Borntraeger
2020-02-10 18:17 ` David Hildenbrand
2020-02-10 18:28 ` Christian Borntraeger
2020-02-10 18:43 ` David Hildenbrand
2020-02-10 18:51 ` Christian Borntraeger
2020-02-18 3:36 ` Tian, Kevin
2020-02-18 6:44 ` Christian Borntraeger
2020-02-07 11:39 ` [PATCH 02/35] KVM: s390/interrupt: do not pin adapter interrupt pages Christian Borntraeger
2020-02-10 12:26 ` David Hildenbrand
2020-02-10 18:38 ` Christian Borntraeger
2020-02-10 19:33 ` David Hildenbrand
2020-02-11 9:23 ` [PATCH v2 RFC] " Christian Borntraeger
2020-02-12 11:52 ` Christian Borntraeger
2020-02-12 12:16 ` David Hildenbrand
2020-02-12 12:22 ` Christian Borntraeger
2020-02-12 12:47 ` David Hildenbrand
2020-02-12 12:39 ` Cornelia Huck
2020-02-12 12:44 ` Christian Borntraeger
2020-02-12 13:07 ` Cornelia Huck
2020-02-10 18:56 ` [PATCH 02/35] KVM: s390/interrupt: do not pin adapter interrupt Ulrich Weigand
2020-02-10 12:40 ` [PATCH 02/35] KVM: s390/interrupt: do not pin adapter interrupt pages David Hildenbrand
2020-02-07 11:39 ` [PATCH 05/35] s390/mm: provide memory management functions for protected KVM guests Christian Borntraeger
2020-02-12 13:42 ` Cornelia Huck
2020-02-13 7:43 ` Christian Borntraeger
2020-02-13 8:44 ` Cornelia Huck
2020-02-14 17:59 ` David Hildenbrand
2020-02-14 21:17 ` Christian Borntraeger
2020-02-07 11:39 ` [PATCH 06/35] s390/mm: add (non)secure page access exceptions handlers Christian Borntraeger
2020-02-14 18:05 ` David Hildenbrand
2020-02-14 19:59 ` Christian Borntraeger [this message]
2020-02-07 11:39 ` [PATCH 10/35] KVM: s390: protvirt: Secure memory is not mergeable Christian Borntraeger
2020-02-07 11:39 ` [PATCH 11/35] KVM: s390/mm: Make pages accessible before destroying the guest Christian Borntraeger
2020-02-14 18:40 ` David Hildenbrand
2020-02-07 11:39 ` [PATCH 21/35] KVM: s390/mm: handle guest unpin events Christian Borntraeger
2020-02-10 14:58 ` Thomas Huth
2020-02-11 13:21 ` Cornelia Huck
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