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Commit 601045bf authored by Radim Krčmář's avatar Radim Krčmář
Browse files

Merge branch 'kvm-ppc-next' of... 

Merge branch 'kvm-ppc-next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into next

Fix for CVE-2016-5412, a denial-of-service vulnerability in HV KVM on
POWER8 machines
parents 912902ce 93d17397

arch/powerpc/kvm/book3s_hv_rmhandlers.S

+250 −212
Original line number Diff line number Diff line
@@ -689,112 +689,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S) 


#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

BEGIN_FTR_SECTION

	b	skip_tm

END_FTR_SECTION_IFCLR(CPU_FTR_TM)



	/* Turn on TM/FP/VSX/VMX so we can restore them. */

	mfmsr	r5

	li	r6, MSR_TM >> 32

	sldi	r6, r6, 32

	or	r5, r5, r6

	ori	r5, r5, MSR_FP

	oris	r5, r5, (MSR_VEC | MSR_VSX)@h

	mtmsrd	r5



	/*

	 * The user may change these outside of a transaction, so they must

	 * always be context switched.

	 */

	ld	r5, VCPU_TFHAR(r4)

	ld	r6, VCPU_TFIAR(r4)

	ld	r7, VCPU_TEXASR(r4)

	mtspr	SPRN_TFHAR, r5

	mtspr	SPRN_TFIAR, r6

	mtspr	SPRN_TEXASR, r7



	ld	r5, VCPU_MSR(r4)

	rldicl. r5, r5, 64 - MSR_TS_S_LG, 62

	beq	skip_tm	/* TM not active in guest */



	/* Make sure the failure summary is set, otherwise we'll program check

	 * when we trechkpt.  It's possible that this might have been not set

	 * on a kvmppc_set_one_reg() call but we shouldn't let this crash the

	 * host.

	 */

	oris	r7, r7, (TEXASR_FS)@h

	mtspr	SPRN_TEXASR, r7



	/*

	 * We need to load up the checkpointed state for the guest.

	 * We need to do this early as it will blow away any GPRs, VSRs and

	 * some SPRs.

	 */



	mr	r31, r4

	addi	r3, r31, VCPU_FPRS_TM

	bl	load_fp_state

	addi	r3, r31, VCPU_VRS_TM

	bl	load_vr_state

	mr	r4, r31

	lwz	r7, VCPU_VRSAVE_TM(r4)

	mtspr	SPRN_VRSAVE, r7



	ld	r5, VCPU_LR_TM(r4)

	lwz	r6, VCPU_CR_TM(r4)

	ld	r7, VCPU_CTR_TM(r4)

	ld	r8, VCPU_AMR_TM(r4)

	ld	r9, VCPU_TAR_TM(r4)

	mtlr	r5

	mtcr	r6

	mtctr	r7

	mtspr	SPRN_AMR, r8

	mtspr	SPRN_TAR, r9



	/*

	 * Load up PPR and DSCR values but don't put them in the actual SPRs

	 * till the last moment to avoid running with userspace PPR and DSCR for

	 * too long.

	 */

	ld	r29, VCPU_DSCR_TM(r4)

	ld	r30, VCPU_PPR_TM(r4)



	std	r2, PACATMSCRATCH(r13) /* Save TOC */



	/* Clear the MSR RI since r1, r13 are all going to be foobar. */

	li	r5, 0

	mtmsrd	r5, 1



	/* Load GPRs r0-r28 */

	reg = 0

	.rept	29

	ld	reg, VCPU_GPRS_TM(reg)(r31)

	reg = reg + 1

	.endr



	mtspr	SPRN_DSCR, r29

	mtspr	SPRN_PPR, r30



	/* Load final GPRs */

	ld	29, VCPU_GPRS_TM(29)(r31)

	ld	30, VCPU_GPRS_TM(30)(r31)

	ld	31, VCPU_GPRS_TM(31)(r31)



	/* TM checkpointed state is now setup.  All GPRs are now volatile. */

	TRECHKPT



	/* Now let's get back the state we need. */

	HMT_MEDIUM

	GET_PACA(r13)

	ld	r29, HSTATE_DSCR(r13)

	mtspr	SPRN_DSCR, r29

	ld	r4, HSTATE_KVM_VCPU(r13)

	ld	r1, HSTATE_HOST_R1(r13)

	ld	r2, PACATMSCRATCH(r13)



	/* Set the MSR RI since we have our registers back. */

	li	r5, MSR_RI

	mtmsrd	r5, 1

skip_tm:

	bl	kvmppc_restore_tm

END_FTR_SECTION_IFSET(CPU_FTR_TM)

#endif



	/* Load guest PMU registers */
@@ -875,12 +771,6 @@ BEGIN_FTR_SECTION 
	/* Skip next section on POWER7 */

	b	8f

END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S)

	/* Turn on TM so we can access TFHAR/TFIAR/TEXASR */

	mfmsr	r8

	li	r0, 1

	rldimi	r8, r0, MSR_TM_LG, 63-MSR_TM_LG

	mtmsrd	r8



	/* Load up POWER8-specific registers */

	ld	r5, VCPU_IAMR(r4)

	lwz	r6, VCPU_PSPB(r4)
@@ -1470,106 +1360,8 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_207S) 


#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

BEGIN_FTR_SECTION

	b	2f

END_FTR_SECTION_IFCLR(CPU_FTR_TM)

	/* Turn on TM. */

	mfmsr	r8

	li	r0, 1

	rldimi	r8, r0, MSR_TM_LG, 63-MSR_TM_LG

	mtmsrd	r8



	ld	r5, VCPU_MSR(r9)

	rldicl. r5, r5, 64 - MSR_TS_S_LG, 62

	beq	1f	/* TM not active in guest. */



	li	r3, TM_CAUSE_KVM_RESCHED



	/* Clear the MSR RI since r1, r13 are all going to be foobar. */

	li	r5, 0

	mtmsrd	r5, 1



	/* All GPRs are volatile at this point. */

	TRECLAIM(R3)



	/* Temporarily store r13 and r9 so we have some regs to play with */

	SET_SCRATCH0(r13)

	GET_PACA(r13)

	std	r9, PACATMSCRATCH(r13)

	ld	r9, HSTATE_KVM_VCPU(r13)



	/* Get a few more GPRs free. */

	std	r29, VCPU_GPRS_TM(29)(r9)

	std	r30, VCPU_GPRS_TM(30)(r9)

	std	r31, VCPU_GPRS_TM(31)(r9)



	/* Save away PPR and DSCR soon so don't run with user values. */

	mfspr	r31, SPRN_PPR

	HMT_MEDIUM

	mfspr	r30, SPRN_DSCR

	ld	r29, HSTATE_DSCR(r13)

	mtspr	SPRN_DSCR, r29



	/* Save all but r9, r13 & r29-r31 */

	reg = 0

	.rept	29

	.if (reg != 9) && (reg != 13)

	std	reg, VCPU_GPRS_TM(reg)(r9)

	.endif

	reg = reg + 1

	.endr

	/* ... now save r13 */

	GET_SCRATCH0(r4)

	std	r4, VCPU_GPRS_TM(13)(r9)

	/* ... and save r9 */

	ld	r4, PACATMSCRATCH(r13)

	std	r4, VCPU_GPRS_TM(9)(r9)



	/* Reload stack pointer and TOC. */

	ld	r1, HSTATE_HOST_R1(r13)

	ld	r2, PACATOC(r13)



	/* Set MSR RI now we have r1 and r13 back. */

	li	r5, MSR_RI

	mtmsrd	r5, 1



	/* Save away checkpinted SPRs. */

	std	r31, VCPU_PPR_TM(r9)

	std	r30, VCPU_DSCR_TM(r9)

	mflr	r5

	mfcr	r6

	mfctr	r7

	mfspr	r8, SPRN_AMR

	mfspr	r10, SPRN_TAR

	std	r5, VCPU_LR_TM(r9)

	stw	r6, VCPU_CR_TM(r9)

	std	r7, VCPU_CTR_TM(r9)

	std	r8, VCPU_AMR_TM(r9)

	std	r10, VCPU_TAR_TM(r9)



	/* Restore r12 as trap number. */

	lwz	r12, VCPU_TRAP(r9)



	/* Save FP/VSX. */

	addi	r3, r9, VCPU_FPRS_TM

	bl	store_fp_state

	addi	r3, r9, VCPU_VRS_TM

	bl	store_vr_state

	mfspr	r6, SPRN_VRSAVE

	stw	r6, VCPU_VRSAVE_TM(r9)

1:

	/*

	 * We need to save these SPRs after the treclaim so that the software

	 * error code is recorded correctly in the TEXASR.  Also the user may

	 * change these outside of a transaction, so they must always be

	 * context switched.

	 */

	mfspr	r5, SPRN_TFHAR

	mfspr	r6, SPRN_TFIAR

	mfspr	r7, SPRN_TEXASR

	std	r5, VCPU_TFHAR(r9)

	std	r6, VCPU_TFIAR(r9)

	std	r7, VCPU_TEXASR(r9)

2:

	bl	kvmppc_save_tm

END_FTR_SECTION_IFSET(CPU_FTR_TM)

#endif



	/* Increment yield count if they have a VPA */
@@ -2301,6 +2093,13 @@ _GLOBAL(kvmppc_h_cede) /* r3 = vcpu pointer, r11 = msr, r13 = paca */ 
	/* save FP state */

	bl	kvmppc_save_fp



#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

BEGIN_FTR_SECTION

	ld	r9, HSTATE_KVM_VCPU(r13)

	bl	kvmppc_save_tm

END_FTR_SECTION_IFSET(CPU_FTR_TM)

#endif



	/*

	 * Set DEC to the smaller of DEC and HDEC, so that we wake

	 * no later than the end of our timeslice (HDEC interrupts
@@ -2377,6 +2176,12 @@ kvm_end_cede: 
	bl	kvmhv_accumulate_time

#endif



#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

BEGIN_FTR_SECTION

	bl	kvmppc_restore_tm

END_FTR_SECTION_IFSET(CPU_FTR_TM)

#endif



	/* load up FP state */

	bl	kvmppc_load_fp
@@ -2694,6 +2499,239 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) 
	mr	r4,r31

	blr



#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

/*

 * Save transactional state and TM-related registers.

 * Called with r9 pointing to the vcpu struct.

 * This can modify all checkpointed registers, but

 * restores r1, r2 and r9 (vcpu pointer) before exit.

 */

kvmppc_save_tm:

	mflr	r0

	std	r0, PPC_LR_STKOFF(r1)



	/* Turn on TM. */

	mfmsr	r8

	li	r0, 1

	rldimi	r8, r0, MSR_TM_LG, 63-MSR_TM_LG

	mtmsrd	r8



	ld	r5, VCPU_MSR(r9)

	rldicl. r5, r5, 64 - MSR_TS_S_LG, 62

	beq	1f	/* TM not active in guest. */



	std	r1, HSTATE_HOST_R1(r13)

	li	r3, TM_CAUSE_KVM_RESCHED



	/* Clear the MSR RI since r1, r13 are all going to be foobar. */

	li	r5, 0

	mtmsrd	r5, 1



	/* All GPRs are volatile at this point. */

	TRECLAIM(R3)



	/* Temporarily store r13 and r9 so we have some regs to play with */

	SET_SCRATCH0(r13)

	GET_PACA(r13)

	std	r9, PACATMSCRATCH(r13)

	ld	r9, HSTATE_KVM_VCPU(r13)



	/* Get a few more GPRs free. */

	std	r29, VCPU_GPRS_TM(29)(r9)

	std	r30, VCPU_GPRS_TM(30)(r9)

	std	r31, VCPU_GPRS_TM(31)(r9)



	/* Save away PPR and DSCR soon so don't run with user values. */

	mfspr	r31, SPRN_PPR

	HMT_MEDIUM

	mfspr	r30, SPRN_DSCR

	ld	r29, HSTATE_DSCR(r13)

	mtspr	SPRN_DSCR, r29



	/* Save all but r9, r13 & r29-r31 */

	reg = 0

	.rept	29

	.if (reg != 9) && (reg != 13)

	std	reg, VCPU_GPRS_TM(reg)(r9)

	.endif

	reg = reg + 1

	.endr

	/* ... now save r13 */

	GET_SCRATCH0(r4)

	std	r4, VCPU_GPRS_TM(13)(r9)

	/* ... and save r9 */

	ld	r4, PACATMSCRATCH(r13)

	std	r4, VCPU_GPRS_TM(9)(r9)



	/* Reload stack pointer and TOC. */

	ld	r1, HSTATE_HOST_R1(r13)

	ld	r2, PACATOC(r13)



	/* Set MSR RI now we have r1 and r13 back. */

	li	r5, MSR_RI

	mtmsrd	r5, 1



	/* Save away checkpinted SPRs. */

	std	r31, VCPU_PPR_TM(r9)

	std	r30, VCPU_DSCR_TM(r9)

	mflr	r5

	mfcr	r6

	mfctr	r7

	mfspr	r8, SPRN_AMR

	mfspr	r10, SPRN_TAR

	std	r5, VCPU_LR_TM(r9)

	stw	r6, VCPU_CR_TM(r9)

	std	r7, VCPU_CTR_TM(r9)

	std	r8, VCPU_AMR_TM(r9)

	std	r10, VCPU_TAR_TM(r9)



	/* Restore r12 as trap number. */

	lwz	r12, VCPU_TRAP(r9)



	/* Save FP/VSX. */

	addi	r3, r9, VCPU_FPRS_TM

	bl	store_fp_state

	addi	r3, r9, VCPU_VRS_TM

	bl	store_vr_state

	mfspr	r6, SPRN_VRSAVE

	stw	r6, VCPU_VRSAVE_TM(r9)

1:

	/*

	 * We need to save these SPRs after the treclaim so that the software

	 * error code is recorded correctly in the TEXASR.  Also the user may

	 * change these outside of a transaction, so they must always be

	 * context switched.

	 */

	mfspr	r5, SPRN_TFHAR

	mfspr	r6, SPRN_TFIAR

	mfspr	r7, SPRN_TEXASR

	std	r5, VCPU_TFHAR(r9)

	std	r6, VCPU_TFIAR(r9)

	std	r7, VCPU_TEXASR(r9)



	ld	r0, PPC_LR_STKOFF(r1)

	mtlr	r0

	blr



/*

 * Restore transactional state and TM-related registers.

 * Called with r4 pointing to the vcpu struct.

 * This potentially modifies all checkpointed registers.

 * It restores r1, r2, r4 from the PACA.

 */

kvmppc_restore_tm:

	mflr	r0

	std	r0, PPC_LR_STKOFF(r1)



	/* Turn on TM/FP/VSX/VMX so we can restore them. */

	mfmsr	r5

	li	r6, MSR_TM >> 32

	sldi	r6, r6, 32

	or	r5, r5, r6

	ori	r5, r5, MSR_FP

	oris	r5, r5, (MSR_VEC | MSR_VSX)@h

	mtmsrd	r5



	/*

	 * The user may change these outside of a transaction, so they must

	 * always be context switched.

	 */

	ld	r5, VCPU_TFHAR(r4)

	ld	r6, VCPU_TFIAR(r4)

	ld	r7, VCPU_TEXASR(r4)

	mtspr	SPRN_TFHAR, r5

	mtspr	SPRN_TFIAR, r6

	mtspr	SPRN_TEXASR, r7



	ld	r5, VCPU_MSR(r4)

	rldicl. r5, r5, 64 - MSR_TS_S_LG, 62

	beqlr		/* TM not active in guest */

	std	r1, HSTATE_HOST_R1(r13)



	/* Make sure the failure summary is set, otherwise we'll program check

	 * when we trechkpt.  It's possible that this might have been not set

	 * on a kvmppc_set_one_reg() call but we shouldn't let this crash the

	 * host.

	 */

	oris	r7, r7, (TEXASR_FS)@h

	mtspr	SPRN_TEXASR, r7



	/*

	 * We need to load up the checkpointed state for the guest.

	 * We need to do this early as it will blow away any GPRs, VSRs and

	 * some SPRs.

	 */



	mr	r31, r4

	addi	r3, r31, VCPU_FPRS_TM

	bl	load_fp_state

	addi	r3, r31, VCPU_VRS_TM

	bl	load_vr_state

	mr	r4, r31

	lwz	r7, VCPU_VRSAVE_TM(r4)

	mtspr	SPRN_VRSAVE, r7



	ld	r5, VCPU_LR_TM(r4)

	lwz	r6, VCPU_CR_TM(r4)

	ld	r7, VCPU_CTR_TM(r4)

	ld	r8, VCPU_AMR_TM(r4)

	ld	r9, VCPU_TAR_TM(r4)

	mtlr	r5

	mtcr	r6

	mtctr	r7

	mtspr	SPRN_AMR, r8

	mtspr	SPRN_TAR, r9



	/*

	 * Load up PPR and DSCR values but don't put them in the actual SPRs

	 * till the last moment to avoid running with userspace PPR and DSCR for

	 * too long.

	 */

	ld	r29, VCPU_DSCR_TM(r4)

	ld	r30, VCPU_PPR_TM(r4)



	std	r2, PACATMSCRATCH(r13) /* Save TOC */



	/* Clear the MSR RI since r1, r13 are all going to be foobar. */

	li	r5, 0

	mtmsrd	r5, 1



	/* Load GPRs r0-r28 */

	reg = 0

	.rept	29

	ld	reg, VCPU_GPRS_TM(reg)(r31)

	reg = reg + 1

	.endr



	mtspr	SPRN_DSCR, r29

	mtspr	SPRN_PPR, r30



	/* Load final GPRs */

	ld	29, VCPU_GPRS_TM(29)(r31)

	ld	30, VCPU_GPRS_TM(30)(r31)

	ld	31, VCPU_GPRS_TM(31)(r31)



	/* TM checkpointed state is now setup.  All GPRs are now volatile. */

	TRECHKPT



	/* Now let's get back the state we need. */

	HMT_MEDIUM

	GET_PACA(r13)

	ld	r29, HSTATE_DSCR(r13)

	mtspr	SPRN_DSCR, r29

	ld	r4, HSTATE_KVM_VCPU(r13)

	ld	r1, HSTATE_HOST_R1(r13)

	ld	r2, PACATMSCRATCH(r13)



	/* Set the MSR RI since we have our registers back. */

	li	r5, MSR_RI

	mtmsrd	r5, 1



	ld	r0, PPC_LR_STKOFF(r1)

	mtlr	r0

	blr

#endif



/*

 * We come here if we get any exception or interrupt while we are

 * executing host real mode code while in guest MMU context.