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FAILED: patch "[PATCH] KVM: PPC: Book3S HV: Save host FSCR in the P7/8 path" failed to apply to 5.13-stable tree

PATCH [email protected] 1 participant 1 message Jul 11, 2021

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The patch below does not apply to the 5.13-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 6ba53317d497dec029bfb040b1daf38328fa00ab Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <[email protected]>
Date: Wed, 26 May 2021 22:58:51 +1000
Subject: [PATCH] KVM: PPC: Book3S HV: Save host FSCR in the P7/8 path

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 [email protected] # v3.14+
Signed-off-by Nicholas Piggin <[email protected]>
Reviewed-by Fabiano Rosas <[email protected]>
Signed-off-by Michael Ellerman <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
arch/powerpc/kvm/book3s_hv.c +0 -1
index 28a80d240b76..13728495ac66 100644
@@ -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);
arch/powerpc/kvm/book3s_hv_rmhandlers.S +7 -0
index 5e634db4809b..004f0d4e665f 100644
@@ -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.