From 1cfbb484de158e378e8971ac40f3082e53ecca55 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 8 Jan 2020 13:43:24 +0000 Subject: KVM: arm/arm64: Correct AArch32 SPSR on exception entry Confusingly, there are three SPSR layouts that a kernel may need to deal with: (1) An AArch64 SPSR_ELx view of an AArch64 pstate (2) An AArch64 SPSR_ELx view of an AArch32 pstate (3) An AArch32 SPSR_* view of an AArch32 pstate When the KVM AArch32 support code deals with SPSR_{EL2,HYP}, it's either dealing with #2 or #3 consistently. On arm64 the PSR_AA32_* definitions match the AArch64 SPSR_ELx view, and on arm the PSR_AA32_* definitions match the AArch32 SPSR_* view. However, when we inject an exception into an AArch32 guest, we have to synthesize the AArch32 SPSR_* that the guest will see. Thus, an AArch64 host needs to synthesize layout #3 from layout #2. This patch adds a new host_spsr_to_spsr32() helper for this, and makes use of it in the KVM AArch32 support code. For arm64 we need to shuffle the DIT bit around, and remove the SS bit, while for arm we can use the value as-is. I've open-coded the bit manipulation for now to avoid having to rework the existing PSR_* definitions into PSR64_AA32_* and PSR32_AA32_* definitions. I hope to perform a more thorough refactoring in future so that we can handle pstate view manipulation more consistently across the kernel tree. Signed-off-by: Mark Rutland Signed-off-by: Marc Zyngier Reviewed-by: Alexandru Elisei Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200108134324.46500-4-mark.rutland@arm.com --- virt/kvm/arm/aarch32.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'virt') diff --git a/virt/kvm/arm/aarch32.c b/virt/kvm/arm/aarch32.c index 773cf1439081..631d397ac81b 100644 --- a/virt/kvm/arm/aarch32.c +++ b/virt/kvm/arm/aarch32.c @@ -129,15 +129,15 @@ static unsigned long get_except32_cpsr(struct kvm_vcpu *vcpu, u32 mode) static void prepare_fault32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset) { - unsigned long new_spsr_value = *vcpu_cpsr(vcpu); - bool is_thumb = (new_spsr_value & PSR_AA32_T_BIT); + unsigned long spsr = *vcpu_cpsr(vcpu); + bool is_thumb = (spsr & PSR_AA32_T_BIT); u32 return_offset = return_offsets[vect_offset >> 2][is_thumb]; u32 sctlr = vcpu_cp15(vcpu, c1_SCTLR); *vcpu_cpsr(vcpu) = get_except32_cpsr(vcpu, mode); /* Note: These now point to the banked copies */ - vcpu_write_spsr(vcpu, new_spsr_value); + vcpu_write_spsr(vcpu, host_spsr_to_spsr32(spsr)); *vcpu_reg32(vcpu, 14) = *vcpu_pc(vcpu) + return_offset; /* Branch to exception vector */ -- cgit v1.2.3