| Message ID | 20210523122101.3247232-1-npiggin@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | KVM: PPC: Book3S HV: Save host FSCR in the P7/8 path | expand |
| Related | show |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (8dbbcb8a8856c6b4e56ae705218d8dad1f9cf1e9) |
| snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64e | success | Build succeeded |
| snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 36 lines checked |
| snowpatch_ozlabs/needsstable | warning | Please consider tagging this patch for stable! |
Excerpts from Nicholas Piggin's message of May 23, 2021 10:21 pm: > Similar to commit 25edcc50d76c ("KVM: PPC: Book3S HV: Save and restore > FSCR in the P9 path"), ensure the P7/8 path saves and restores the host > FSCR. The logic explained in that patch actually applies there to the > old path well: a context switch can be made before kvmppc_vcpu_run_hv > restores the host FSCR and returns. > > Fixes: b005255e12a3 ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs") > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > --- > arch/powerpc/kvm/book3s_hv_rmhandlers.S | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S > index 5e634db4809b..2b98e710c7a1 100644 > --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S > +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S > @@ -44,7 +44,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) > #define NAPPING_UNSPLIT 3 > > /* Stack frame offsets for kvmppc_hv_entry */ > -#define SFS 208 > +#define SFS 216 > #define STACK_SLOT_TRAP (SFS-4) > #define STACK_SLOT_SHORT_PATH (SFS-8) > #define STACK_SLOT_TID (SFS-16) > @@ -59,8 +59,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) > #define STACK_SLOT_UAMOR (SFS-88) > #define STACK_SLOT_DAWR1 (SFS-96) > #define STACK_SLOT_DAWRX1 (SFS-104) > +#define STACK_SLOT_FSCR (SFS-112) > /* the following is used by the P9 short path */ > -#define STACK_SLOT_NVGPRS (SFS-152) /* 18 gprs */ > +#define STACK_SLOT_NVGPRS (SFS-160) /* 18 gprs */ Actually, hmm.. this is wrong because nvgprs are subtracted from this offset. But then I can't work out why 95a6432ce9038 raised SFS from 160 to 208. Thanks, Nick
Nicholas Piggin <npiggin@gmail.com> writes: > Similar to commit 25edcc50d76c ("KVM: PPC: Book3S HV: Save and restore > FSCR in the P9 path"), ensure the P7/8 path saves and restores the host > FSCR. The logic explained in that patch actually applies there to the > old path well: a context switch can be made before kvmppc_vcpu_run_hv > restores the host FSCR and returns. > > Fixes: b005255e12a3 ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs") > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > --- > arch/powerpc/kvm/book3s_hv_rmhandlers.S | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S > index 5e634db4809b..2b98e710c7a1 100644 > --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S > +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S > @@ -44,7 +44,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) > #define NAPPING_UNSPLIT 3 > > /* Stack frame offsets for kvmppc_hv_entry */ > -#define SFS 208 > +#define SFS 216 > #define STACK_SLOT_TRAP (SFS-4) > #define STACK_SLOT_SHORT_PATH (SFS-8) > #define STACK_SLOT_TID (SFS-16) > @@ -59,8 +59,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) > #define STACK_SLOT_UAMOR (SFS-88) > #define STACK_SLOT_DAWR1 (SFS-96) > #define STACK_SLOT_DAWRX1 (SFS-104) > +#define STACK_SLOT_FSCR (SFS-112) > /* the following is used by the P9 short path */ > -#define STACK_SLOT_NVGPRS (SFS-152) /* 18 gprs */ > +#define STACK_SLOT_NVGPRS (SFS-160) /* 18 gprs */ > > /* > * Call kvmppc_hv_entry in real mode. > @@ -686,6 +687,8 @@ BEGIN_FTR_SECTION > std r6, STACK_SLOT_DAWR0(r1) > std r7, STACK_SLOT_DAWRX0(r1) > std r8, STACK_SLOT_IAMR(r1) > + mfspr r5, SPRN_FSCR > + std r5, STACK_SLOT_FSCR(r1) > END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) > BEGIN_FTR_SECTION > mfspr r6, SPRN_DAWR1 > @@ -1663,6 +1666,10 @@ FTR_SECTION_ELSE > ld r7, STACK_SLOT_HFSCR(r1) > mtspr SPRN_HFSCR, r7 > ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300) > +BEGIN_FTR_SECTION > + ld r5, STACK_SLOT_FSCR(r1) > + mtspr SPRN_FSCR, r5 > +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) > /* > * Restore various registers to 0, where non-zero values > * set by the guest could disrupt the host. So it seems this line in kvmppc_vcpu_run_hv loses its purpose now? do{ (...) } while (is_kvmppc_resume_guest(r)); /* Restore userspace EBB and other register values */ if (cpu_has_feature(CPU_FTR_ARCH_207S)) { mtspr(SPRN_EBBHR, ebb_regs[0]); mtspr(SPRN_EBBRR, ebb_regs[1]); mtspr(SPRN_BESCR, ebb_regs[2]); mtspr(SPRN_TAR, user_tar); ---> mtspr(SPRN_FSCR, current->thread.fscr); }
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 5e634db4809b..2b98e710c7a1 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -44,7 +44,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) #define NAPPING_UNSPLIT 3 /* Stack frame offsets for kvmppc_hv_entry */ -#define SFS 208 +#define SFS 216 #define STACK_SLOT_TRAP (SFS-4) #define STACK_SLOT_SHORT_PATH (SFS-8) #define STACK_SLOT_TID (SFS-16) @@ -59,8 +59,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300) #define STACK_SLOT_UAMOR (SFS-88) #define STACK_SLOT_DAWR1 (SFS-96) #define STACK_SLOT_DAWRX1 (SFS-104) +#define STACK_SLOT_FSCR (SFS-112) /* the following is used by the P9 short path */ -#define STACK_SLOT_NVGPRS (SFS-152) /* 18 gprs */ +#define STACK_SLOT_NVGPRS (SFS-160) /* 18 gprs */ /* * Call kvmppc_hv_entry in real mode. @@ -686,6 +687,8 @@ BEGIN_FTR_SECTION std r6, STACK_SLOT_DAWR0(r1) std r7, STACK_SLOT_DAWRX0(r1) std r8, STACK_SLOT_IAMR(r1) + mfspr r5, SPRN_FSCR + std r5, STACK_SLOT_FSCR(r1) END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) BEGIN_FTR_SECTION mfspr r6, SPRN_DAWR1 @@ -1663,6 +1666,10 @@ FTR_SECTION_ELSE ld r7, STACK_SLOT_HFSCR(r1) mtspr SPRN_HFSCR, r7 ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300) +BEGIN_FTR_SECTION + ld r5, STACK_SLOT_FSCR(r1) + mtspr SPRN_FSCR, r5 +END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) /* * Restore various registers to 0, where non-zero values * set by the guest could disrupt the host.
Similar to commit 25edcc50d76c ("KVM: PPC: Book3S HV: Save and restore FSCR in the P9 path"), ensure the P7/8 path saves and restores the host FSCR. The logic explained in that patch actually applies there to the old path well: a context switch can be made before kvmppc_vcpu_run_hv restores the host FSCR and returns. Fixes: b005255e12a3 ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/kvm/book3s_hv_rmhandlers.S | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)