On 1/18/22 18:27, Matthew Rosato wrote:
On 1/18/22 6:05 AM, Pierre Morel wrote:
On 1/14/22 21:31, Matthew Rosato wrote:
For faster handling of PCI translation refreshes, intercept in KVM
and call the associated handler.
Signed-off-by: Matthew Rosato <mjrosato@xxxxxxxxxxxxx>
---
arch/s390/kvm/priv.c | 46 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 417154b314a6..5b65c1830de2 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -29,6 +29,7 @@
#include <asm/ap.h>
#include "gaccess.h"
#include "kvm-s390.h"
+#include "pci.h"
#include "trace.h"
static int handle_ri(struct kvm_vcpu *vcpu)
@@ -335,6 +336,49 @@ static int handle_rrbe(struct kvm_vcpu *vcpu)
return 0;
}
+static int handle_rpcit(struct kvm_vcpu *vcpu)
+{
+ int reg1, reg2;
+ u8 status;
+ int rc;
+
+ if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
+ return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
+
+ /* If the host doesn't support PCI, it must be an emulated
device */
+ if (!IS_ENABLED(CONFIG_PCI))
+ return -EOPNOTSUPP;
AFAIU this makes also sure that the following code is not compiled in
case PCI is not supported.
I am not very used to compilation options, is it true with all our
compilers and options?
Or do we have to specify a compiler version?
Another concern is, shouldn't we use IS_ENABLED(CONFIG_VFIO_PCI) ?
Same idea as in the other thread -- What we are trying to protect
against here is referencing symbols that won't be linked (like
zpci_refresh_trans, or the aift->mdd a few lines below)
It is indeed true that we should never need to handle the rpcit
intercept in KVM if CONFIG_VFIO_PCI=n -- but the necessary symbols/code
are linked at least, so we can just let the SHM logic sort this out.
When CONFIG_PCI=y|m, arch/s390/kvm/pci.o will be linked and so we can
compare the function handle against afit->mdd (check to see if the
device is emulated) and use this to determine whether or not to
immediately send to userspace -- And if CONFIG_VFIO_PCI=n, a SHM bit
will always be on and so we'll always go to userspace via this check.
So we agree.
But as I I said somewhere else I wonder if CONFIG_VFIO_PCI_ZDEV would
not even be better here.
+
+ kvm_s390_get_regs_rre(vcpu, ®1, ®2);
+
+ /* If the device has a SHM bit on, let userspace take care of
this */
+ if (((vcpu->run->s.regs.gprs[reg1] >> 32) & aift->mdd) != 0)
+ return -EOPNOTSUPP;
+
+ rc = kvm_s390_pci_refresh_trans(vcpu, vcpu->run->s.regs.gprs[reg1],
+ vcpu->run->s.regs.gprs[reg2],
+ vcpu->run->s.regs.gprs[reg2+1],
+ &status);
+
+ switch (rc) {
+ case 0:
+ kvm_s390_set_psw_cc(vcpu, 0);
+ break;
+ case -EOPNOTSUPP:
+ return -EOPNOTSUPP;
+ default:
+ vcpu->run->s.regs.gprs[reg1] &= 0xffffffff00ffffffUL;
+ vcpu->run->s.regs.gprs[reg1] |= (u64) status << 24;
+ if (status != 0)
+ kvm_s390_set_psw_cc(vcpu, 1);
+ else
+ kvm_s390_set_psw_cc(vcpu, 3);
+ break;
+ }
+
+ return 0;
+}
+
#define SSKE_NQ 0x8
#define SSKE_MR 0x4
#define SSKE_MC 0x2
@@ -1275,6 +1319,8 @@ int kvm_s390_handle_b9(struct kvm_vcpu *vcpu)
return handle_essa(vcpu);
case 0xaf:
return handle_pfmf(vcpu);
+ case 0xd3:
+ return handle_rpcit(vcpu);
default:
return -EOPNOTSUPP;
}
--
Pierre Morel
IBM Lab Boeblingen
