KVM: arm64: Change 32-bit handling of VM system registers (52f6c4f0) · Commits · 戴 / test

We currently handle 32-bit accesses to trapped VM system registers using the 32-bit index into the coproc array on the vcpu structure, which is a union of the coproc array and the sysreg array. Since all the 32-bit coproc indices are created to correspond to the architectural mapping between 64-bit system registers and 32-bit coprocessor registers, and because the AArch64 system registers are the double in size of the AArch32 coprocessor registers, we can always find the system register entry that we must update by dividing the 32-bit coproc index by 2. This is going to make our lives much easier when we have to start accessing system registers that use deferred save/restore and might have to be read directly from the physical CPU. Reviewed-by:

Andrew Jones <drjones@redhat.com> Reviewed-by:

Marc Zyngier <marc.zyngier@arm.com> Signed-off-by:

Christoffer Dall <christoffer.dall@linaro.org> Signed-off-by:

Marc Zyngier <marc.zyngier@arm.com>

arch/arm64/include/asm/kvm_host.h

+0 −8

Original line number	Diff line number	Diff line
		@@ -295,14 +295,6 @@ struct kvm_vcpu_arch {
		#define vcpu_cp14(v,r) ((v)->arch.ctxt.copro[(r)])
		#define vcpu_cp15(v,r) ((v)->arch.ctxt.copro[(r)])

		#ifdef CONFIG_CPU_BIG_ENDIAN
		#define vcpu_cp15_64_high(v,r) vcpu_cp15((v),(r))
		#define vcpu_cp15_64_low(v,r) vcpu_cp15((v),(r) + 1)
		#else
		#define vcpu_cp15_64_high(v,r) vcpu_cp15((v),(r) + 1)
		#define vcpu_cp15_64_low(v,r) vcpu_cp15((v),(r))
		#endif

		struct kvm_vm_stat {
		ulong remote_tlb_flush;
		};

arch/arm64/kvm/sys_regs.c

+15 −5

Original line number	Diff line number	Diff line
		@@ -121,16 +121,26 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu,
		const struct sys_reg_desc *r)
		{
		bool was_enabled = vcpu_has_cache_enabled(vcpu);
		u64 val;
		int reg = r->reg;

		BUG_ON(!p->is_write);

		if (!p->is_aarch32) {
		vcpu_sys_reg(vcpu, r->reg) = p->regval;
		/* See the 32bit mapping in kvm_host.h */
		if (p->is_aarch32)
		reg = r->reg / 2;

		if (!p->is_aarch32 \|\| !p->is_32bit) {
		val = p->regval;
		} else {
		if (!p->is_32bit)
		vcpu_cp15_64_high(vcpu, r->reg) = upper_32_bits(p->regval);
		vcpu_cp15_64_low(vcpu, r->reg) = lower_32_bits(p->regval);
		val = vcpu_sys_reg(vcpu, reg);
		if (r->reg % 2)
		val = (p->regval << 32) \| (u64)lower_32_bits(val);
		else
		val = ((u64)upper_32_bits(val) << 32) \|
		lower_32_bits(p->regval);
		}
		vcpu_sys_reg(vcpu, reg) = val;

		kvm_toggle_cache(vcpu, was_enabled);
		return true;

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