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Commit 4c47eb1c authored by Marc Zyngier's avatar Marc Zyngier Committed by Radim Krčmář
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arm64: KVM: VHE: Context switch MDSCR_EL1 



The kprobe enablement work has uncovered that changes made by
a guest to MDSCR_EL1 were propagated to the host when VHE was
enabled, leading to unexpected exception being delivered.

Moving this register to the list of registers that are always
context-switched fixes the issue.

Fixes: 9c6c3568 ("arm64: KVM: VHE: Split save/restore of registers shared between guest and host")
Cc: stable@vger.kernel.org #4.6
Reported-by: default avatarTirumalesh Chalamarla <Tirumalesh.Chalamarla@cavium.com>
Tested-by: default avatarTirumalesh Chalamarla <Tirumalesh.Chalamarla@cavium.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarRadim Krčmář <rkrcmar@redhat.com>
parent b244c9fc

arch/arm64/kvm/hyp/sysreg-sr.c

+4 −4
Original line number Diff line number Diff line
@@ -27,8 +27,8 @@ static void __hyp_text __sysreg_do_nothing(struct kvm_cpu_context *ctxt) { } 
/*

 * Non-VHE: Both host and guest must save everything.

 *

 * VHE: Host must save tpidr*_el[01], actlr_el1, sp0, pc, pstate, and

 * guest must save everything.

 * VHE: Host must save tpidr*_el[01], actlr_el1, mdscr_el1, sp0, pc,

 * pstate, and guest must save everything.

 */



static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt)
@@ -37,6 +37,7 @@ static void __hyp_text __sysreg_save_common_state(struct kvm_cpu_context *ctxt) 
	ctxt->sys_regs[TPIDR_EL0]	= read_sysreg(tpidr_el0);

	ctxt->sys_regs[TPIDRRO_EL0]	= read_sysreg(tpidrro_el0);

	ctxt->sys_regs[TPIDR_EL1]	= read_sysreg(tpidr_el1);

	ctxt->sys_regs[MDSCR_EL1]	= read_sysreg(mdscr_el1);

	ctxt->gp_regs.regs.sp		= read_sysreg(sp_el0);

	ctxt->gp_regs.regs.pc		= read_sysreg_el2(elr);

	ctxt->gp_regs.regs.pstate	= read_sysreg_el2(spsr);
@@ -61,7 +62,6 @@ static void __hyp_text __sysreg_save_state(struct kvm_cpu_context *ctxt) 
	ctxt->sys_regs[AMAIR_EL1]	= read_sysreg_el1(amair);

	ctxt->sys_regs[CNTKCTL_EL1]	= read_sysreg_el1(cntkctl);

	ctxt->sys_regs[PAR_EL1]		= read_sysreg(par_el1);

	ctxt->sys_regs[MDSCR_EL1]	= read_sysreg(mdscr_el1);



	ctxt->gp_regs.sp_el1		= read_sysreg(sp_el1);

	ctxt->gp_regs.elr_el1		= read_sysreg_el1(elr);
@@ -90,6 +90,7 @@ static void __hyp_text __sysreg_restore_common_state(struct kvm_cpu_context *ctx 
	write_sysreg(ctxt->sys_regs[TPIDR_EL0],	  tpidr_el0);

	write_sysreg(ctxt->sys_regs[TPIDRRO_EL0], tpidrro_el0);

	write_sysreg(ctxt->sys_regs[TPIDR_EL1],	  tpidr_el1);

	write_sysreg(ctxt->sys_regs[MDSCR_EL1],	  mdscr_el1);

	write_sysreg(ctxt->gp_regs.regs.sp,	  sp_el0);

	write_sysreg_el2(ctxt->gp_regs.regs.pc,	  elr);

	write_sysreg_el2(ctxt->gp_regs.regs.pstate, spsr);
@@ -114,7 +115,6 @@ static void __hyp_text __sysreg_restore_state(struct kvm_cpu_context *ctxt) 
	write_sysreg_el1(ctxt->sys_regs[AMAIR_EL1],	amair);

	write_sysreg_el1(ctxt->sys_regs[CNTKCTL_EL1], 	cntkctl);

	write_sysreg(ctxt->sys_regs[PAR_EL1],		par_el1);

	write_sysreg(ctxt->sys_regs[MDSCR_EL1],		mdscr_el1);



	write_sysreg(ctxt->gp_regs.sp_el1,		sp_el1);

	write_sysreg_el1(ctxt->gp_regs.elr_el1,		elr);