| Message ID | 20180403042142.14134-1-nikunj@linux.vnet.ibm.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v2] broken_sc1: check for H_PRIVILEGE | expand |
On 03.04.2018 06:21, Nikunj A Dadhania wrote: > Recently, found that when DAWR was disabled by linux kernel, the hcall started > returning H_UNSUPPORTED, and VM did not boot up as broken_sc1 patched up SC > calls falsely. > > Instead of checking for various returns, check if its not in privilege mode and > patch sc1 in that case. > > CC: Michael Ellerman <michael@ellerman.id.au> > CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> > Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> > --- > lib/libhvcall/brokensc1.c | 10 +++++----- > lib/libhvcall/libhvcall.h | 1 + > 2 files changed, 6 insertions(+), 5 deletions(-) Reviewed-by: Thomas Huth <thuth@redhat.com>
Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> writes: > Recently, found that when DAWR was disabled by linux kernel, the hcall started > returning H_UNSUPPORTED, and VM did not boot up as broken_sc1 patched up SC > calls falsely. > > Instead of checking for various returns, check if its not in privilege mode and > patch sc1 in that case. > > CC: Michael Ellerman <michael@ellerman.id.au> > CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> > Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> Thanks for doing this. We may never update the kernel to return H_UNSUPPORTED, but at least we won't get bitten by this horrible^H^H^Hawesome PR KVM hack again. cheers > diff --git a/lib/libhvcall/brokensc1.c b/lib/libhvcall/brokensc1.c > index e6387e0..d97ae77 100644 > --- a/lib/libhvcall/brokensc1.c > +++ b/lib/libhvcall/brokensc1.c > @@ -47,13 +47,13 @@ static int check_broken_sc1(void) > * supervisor mode. > */ > r = hcall(INS_SC1, H_SET_DABR, 0); > - if (r == H_SUCCESS || r == H_HARDWARE) { > - /* All is fine */ > - return 0; > + if (r == H_PRIVILEGE) { > + /* We found a broken sc1 host! */ > + return 1; > } > > - /* We found a broken sc1 host! */ > - return 1; > + /* All is fine */ > + return 0; > } > > int patch_broken_sc1(void *start, void *end, uint32_t *test_ins) > diff --git a/lib/libhvcall/libhvcall.h b/lib/libhvcall/libhvcall.h > index 3fa4398..caa4d6d 100644 > --- a/lib/libhvcall/libhvcall.h > +++ b/lib/libhvcall/libhvcall.h > @@ -3,6 +3,7 @@ > > #define H_SUCCESS 0 > #define H_HARDWARE -1 > +#define H_PRIVILEGE -3 /* Caller not privileged */ > > #define H_GET_TCE 0x1C > #define H_PUT_TCE 0x20 > -- > 2.14.3
On 3/4/18 2:21 pm, Nikunj A Dadhania wrote: > Recently, found that when DAWR was disabled by linux kernel, the hcall started > returning H_UNSUPPORTED, and VM did not boot up as broken_sc1 patched up SC > calls falsely. > > Instead of checking for various returns, check if its not in privilege mode and > patch sc1 in that case. > > CC: Michael Ellerman <michael@ellerman.id.au> > CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> > Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> Thanks, applied. > --- > lib/libhvcall/brokensc1.c | 10 +++++----- > lib/libhvcall/libhvcall.h | 1 + > 2 files changed, 6 insertions(+), 5 deletions(-) > > diff --git a/lib/libhvcall/brokensc1.c b/lib/libhvcall/brokensc1.c > index e6387e0..d97ae77 100644 > --- a/lib/libhvcall/brokensc1.c > +++ b/lib/libhvcall/brokensc1.c > @@ -47,13 +47,13 @@ static int check_broken_sc1(void) > * supervisor mode. > */ > r = hcall(INS_SC1, H_SET_DABR, 0); > - if (r == H_SUCCESS || r == H_HARDWARE) { > - /* All is fine */ > - return 0; > + if (r == H_PRIVILEGE) { > + /* We found a broken sc1 host! */ > + return 1; > } > > - /* We found a broken sc1 host! */ > - return 1; > + /* All is fine */ > + return 0; > } > > int patch_broken_sc1(void *start, void *end, uint32_t *test_ins) > diff --git a/lib/libhvcall/libhvcall.h b/lib/libhvcall/libhvcall.h > index 3fa4398..caa4d6d 100644 > --- a/lib/libhvcall/libhvcall.h > +++ b/lib/libhvcall/libhvcall.h > @@ -3,6 +3,7 @@ > > #define H_SUCCESS 0 > #define H_HARDWARE -1 > +#define H_PRIVILEGE -3 /* Caller not privileged */ > > #define H_GET_TCE 0x1C > #define H_PUT_TCE 0x20 >
diff --git a/lib/libhvcall/brokensc1.c b/lib/libhvcall/brokensc1.c index e6387e0..d97ae77 100644 --- a/lib/libhvcall/brokensc1.c +++ b/lib/libhvcall/brokensc1.c @@ -47,13 +47,13 @@ static int check_broken_sc1(void) * supervisor mode. */ r = hcall(INS_SC1, H_SET_DABR, 0); - if (r == H_SUCCESS || r == H_HARDWARE) { - /* All is fine */ - return 0; + if (r == H_PRIVILEGE) { + /* We found a broken sc1 host! */ + return 1; } - /* We found a broken sc1 host! */ - return 1; + /* All is fine */ + return 0; } int patch_broken_sc1(void *start, void *end, uint32_t *test_ins) diff --git a/lib/libhvcall/libhvcall.h b/lib/libhvcall/libhvcall.h index 3fa4398..caa4d6d 100644 --- a/lib/libhvcall/libhvcall.h +++ b/lib/libhvcall/libhvcall.h @@ -3,6 +3,7 @@ #define H_SUCCESS 0 #define H_HARDWARE -1 +#define H_PRIVILEGE -3 /* Caller not privileged */ #define H_GET_TCE 0x1C #define H_PUT_TCE 0x20
Recently, found that when DAWR was disabled by linux kernel, the hcall started returning H_UNSUPPORTED, and VM did not boot up as broken_sc1 patched up SC calls falsely. Instead of checking for various returns, check if its not in privilege mode and patch sc1 in that case. CC: Michael Ellerman <michael@ellerman.id.au> CC: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> --- lib/libhvcall/brokensc1.c | 10 +++++----- lib/libhvcall/libhvcall.h | 1 + 2 files changed, 6 insertions(+), 5 deletions(-)