Commit 4de06e4c authored by Oliver Upton's avatar Oliver Upton Committed by Marc Zyngier
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KVM: arm64: Add a visibility bit to ignore user writes 



We're about to ignore writes to AArch32 ID registers on AArch64-only
systems. Add a bit to indicate a register is handled as write ignore
when accessed from userspace.

Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
Reviewed-by: default avatarReiji Watanabe <reijiw@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220913094441.3957645-6-oliver.upton@linux.dev
parent 5d9a718b

arch/arm64/kvm/sys_regs.c

+3 −0
Original line number Diff line number Diff line
@@ -2775,6 +2775,9 @@ int kvm_sys_reg_set_user(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg, 
	if (!r)

		return -ENOENT;



	if (sysreg_user_write_ignore(vcpu, r))

		return 0;



	if (r->set_user) {

		ret = (r->set_user)(vcpu, r, val);

	} else {

arch/arm64/kvm/sys_regs.h

+7 −0
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ struct sys_reg_desc { 


#define REG_HIDDEN		(1 << 0) /* hidden from userspace and guest */

#define REG_RAZ			(1 << 1) /* RAZ from userspace and guest */

#define REG_USER_WI		(1 << 2) /* WI from userspace only */



static __printf(2, 3)

inline void print_sys_reg_msg(const struct sys_reg_params *p,
@@ -157,6 +158,12 @@ static inline bool sysreg_visible_as_raz(const struct kvm_vcpu *vcpu, 
	return sysreg_visibility(vcpu, r) & REG_RAZ;

}



static inline bool sysreg_user_write_ignore(const struct kvm_vcpu *vcpu,

					    const struct sys_reg_desc *r)

{

	return sysreg_visibility(vcpu, r) & REG_USER_WI;

}



static inline int cmp_sys_reg(const struct sys_reg_desc *i1,

			      const struct sys_reg_desc *i2)

{