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KVM: PPC: Book3S HV: Save host FSCR in the P7/8 path 

Similar to commit 25edcc50d7 ("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.

Now both the p9 and the p7/8 paths now save and restore their FSCR, it
no longer needs to be restored at the end of kvmppc_vcpu_run_hv

Fixes: b005255e12 ("KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs")
Cc: stable@vger.kernel.org # v3.14+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210526125851.3436735-1-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2021-05-26 22:58:51 +10:00 committed by Michael Ellerman
parent 5362a4b6ee
commit 1438709e63
2 changed files with 7 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/powerpc/kvm/book3s_hv.c
View File

@ -4455,7 +4455,6 @@ static int kvmppc_vcpu_run_hv(struct kvm_vcpu *vcpu)
mtspr(SPRN_EBBRR, ebb_regs[1]);
mtspr(SPRN_BESCR, ebb_regs[2]);
mtspr(SPRN_TAR, user_tar);
mtspr(SPRN_FSCR, current->thread.fscr);
}
mtspr(SPRN_VRSAVE, user_vrsave);

7
arch/powerpc/kvm/book3s_hv_rmhandlers.S
View File

@ -59,6 +59,7 @@ 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 */
@ -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.