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author | Tony Krowiak <akrowiak@linux.ibm.com> | 2023-08-15 14:43:33 -0400 |
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committer | Heiko Carstens <hca@linux.ibm.com> | 2023-08-18 15:24:39 +0200 |
commit | f88fb1335733029b4630fb93cfaad349a81e57b2 (patch) | |
tree | 32497b7faca0a5949e65acbcc8ca7bc7cccc70a9 /drivers/s390 | |
parent | fb5040ef7f707525d0681cf6bfe424ccd1aadab7 (diff) | |
download | linux-stable-f88fb1335733029b4630fb93cfaad349a81e57b2.tar.gz linux-stable-f88fb1335733029b4630fb93cfaad349a81e57b2.tar.bz2 linux-stable-f88fb1335733029b4630fb93cfaad349a81e57b2.zip |
s390/vfio-ap: make sure nib is shared
Since the NIB is visible by HW, KVM and the (PV) guest it needs to be
in non-secure or secure but shared storage. Return code 6 is used to
indicate to a PV guest that its NIB would be on secure, unshared
storage and therefore the NIB address is invalid.
Unfortunately we have no easy way to check if a page is unshared after
vfio_pin_pages() since it will automatically export an unshared page
if the UV pin shared call did not succeed due to a page being in
unshared state.
Therefore we use the fact that UV pinning it a second time is a nop
but trying to pin an exported page is an error (0x102). If we
encounter this error, we do a vfio unpin and import the page again,
since vfio_pin_pages() exported it.
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
Acked-by: Halil Pasic <pasic@linux.ibm.com>
Tested-by: Viktor Mihajlovski <mihajlov@linux.ibm.com>
Link: https://lore.kernel.org/r/20230815184333.6554-13-akrowiak@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'drivers/s390')
-rw-r--r-- | drivers/s390/crypto/vfio_ap_ops.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c index 8bda52c46df0..0509f80622cd 100644 --- a/drivers/s390/crypto/vfio_ap_ops.c +++ b/drivers/s390/crypto/vfio_ap_ops.c @@ -359,6 +359,28 @@ static int vfio_ap_validate_nib(struct kvm_vcpu *vcpu, dma_addr_t *nib) return 0; } +static int ensure_nib_shared(unsigned long addr, struct gmap *gmap) +{ + int ret; + + /* + * The nib has to be located in shared storage since guest and + * host access it. vfio_pin_pages() will do a pin shared and + * if that fails (possibly because it's not a shared page) it + * calls export. We try to do a second pin shared here so that + * the UV gives us an error code if we try to pin a non-shared + * page. + * + * If the page is already pinned shared the UV will return a success. + */ + ret = uv_pin_shared(addr); + if (ret) { + /* vfio_pin_pages() likely exported the page so let's re-import */ + gmap_convert_to_secure(gmap, addr); + } + return ret; +} + /** * vfio_ap_irq_enable - Enable Interruption for a APQN * @@ -422,6 +444,14 @@ static struct ap_queue_status vfio_ap_irq_enable(struct vfio_ap_queue *q, h_nib = page_to_phys(h_page) | (nib & ~PAGE_MASK); aqic_gisa.gisc = isc; + /* NIB in non-shared storage is a rc 6 for PV guests */ + if (kvm_s390_pv_cpu_is_protected(vcpu) && + ensure_nib_shared(h_nib & PAGE_MASK, kvm->arch.gmap)) { + vfio_unpin_pages(&q->matrix_mdev->vdev, nib, 1); + status.response_code = AP_RESPONSE_INVALID_ADDRESS; + return status; + } + nisc = kvm_s390_gisc_register(kvm, isc); if (nisc < 0) { VFIO_AP_DBF_WARN("%s: gisc registration failed: nisc=%d, isc=%d, apqn=%#04x\n", |