From 1438709e6328925ef496dafd467dbd0353137434 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Wed, 26 May 2021 22:58:51 +1000
Subject: [PATCH] KVM: PPC: Book3S HV: Save host FSCR in the P7/8 path
References: bsc#1065729
Patch-mainline: v5.13-rc5
Git-commit: 1438709e6328925ef496dafd467dbd0353137434
Alt-commit: 6ba53317d497dec029bfb040b1daf38328fa00ab
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.
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: b005255e12a3 ("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
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/kvm/book3s_hv.c | 1 -
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 7 +++++++
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 28a80d240b76..13728495ac66 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -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);
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -56,6 +56,7 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_300)
#define STACK_SLOT_HFSCR (SFS-72)
#define STACK_SLOT_AMR (SFS-80)
#define STACK_SLOT_UAMOR (SFS-88)
+#define STACK_SLOT_FSCR (SFS-96)
/* the following is used by the P9 short path */
#define STACK_SLOT_NVGPRS (SFS-152) /* 18 gprs */
@@ -711,6 +712,8 @@ BEGIN_FTR_SECTION
std r6, STACK_SLOT_DAWR(r1)
std r7, STACK_SLOT_DAWRX(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)
mfspr r5, SPRN_AMR
@@ -1624,6 +1627,10 @@ 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.
--
2.31.1