From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Wed, 19 Nov 2014 12:02:29 +0100 Subject: [PATCH] arm/arm64: KVM: Handle traps of ICC_SRE_EL1 as RAZ/WI Message-ID: <1416394949-23496-1-git-send-email-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org From: Christoffer Dall When running on a system with a GICv3, we currenly don't allow the guest to access the system register interface of the GICv3. We do this by clearing the ICC_SRE_EL2.Enable, which causes all guest accesses to ICC_SRE_EL1 to trap to EL2 and causes all guest accesses to other ICC_ registers to cause an undefined exception in the guest. However, we currently don't handle the trap of guest accesses to ICC_SRE_EL1 and will spill out a warning. The trap just needs to handle the access as RAZ/WI, and a guest that tries to prod this register and set ICC_SRE_EL1.SRE=1, must read back the value (which Linux already does) to see if it succeeded, and will thus observe that ICC_SRE_EL1.SRE was not set. Add the simple trap handler in the sorted table of the system registers. Signed-off-by: Christoffer Dall [ardb: added 32-bit counterpart] Signed-off-by: Ard Biesheuvel -- v2: added 32-bit counterpart, renaming pm_fake to trap_raz_wi in the process, hence the additional changes on that side --- arch/arm/kvm/coproc.c | 49 +++++++++++++++++++++++++---------------------- arch/arm64/kvm/sys_regs.c | 5 +++++ 2 files changed, 31 insertions(+), 23 deletions(-) diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c index 7928dbdf2102..a7cf90dd51ff 100644 --- a/arch/arm/kvm/coproc.c +++ b/arch/arm/kvm/coproc.c @@ -268,6 +268,16 @@ bool access_sctlr(struct kvm_vcpu *vcpu, return true; } +static bool trap_raz_wi(struct kvm_vcpu *vcpu, + const struct coproc_params *p, + const struct coproc_reg *r) +{ + if (p->is_write) + return ignore_write(vcpu, p); + else + return read_zero(vcpu, p); +} + /* * We could trap ID_DFR0 and tell the guest we don't support performance * monitoring. Unfortunately the patch to make the kernel check ID_DFR0 was @@ -277,29 +287,19 @@ bool access_sctlr(struct kvm_vcpu *vcpu, * must always support PMCCNTR (the cycle counter): we just RAZ/WI for * all PM registers, which doesn't crash the guest kernel at least. */ -static bool pm_fake(struct kvm_vcpu *vcpu, - const struct coproc_params *p, - const struct coproc_reg *r) -{ - if (p->is_write) - return ignore_write(vcpu, p); - else - return read_zero(vcpu, p); -} - -#define access_pmcr pm_fake -#define access_pmcntenset pm_fake -#define access_pmcntenclr pm_fake -#define access_pmovsr pm_fake -#define access_pmselr pm_fake -#define access_pmceid0 pm_fake -#define access_pmceid1 pm_fake -#define access_pmccntr pm_fake -#define access_pmxevtyper pm_fake -#define access_pmxevcntr pm_fake -#define access_pmuserenr pm_fake -#define access_pmintenset pm_fake -#define access_pmintenclr pm_fake +#define access_pmcr trap_raz_wi +#define access_pmcntenset trap_raz_wi +#define access_pmcntenclr trap_raz_wi +#define access_pmovsr trap_raz_wi +#define access_pmselr trap_raz_wi +#define access_pmceid0 trap_raz_wi +#define access_pmceid1 trap_raz_wi +#define access_pmccntr trap_raz_wi +#define access_pmxevtyper trap_raz_wi +#define access_pmxevcntr trap_raz_wi +#define access_pmuserenr trap_raz_wi +#define access_pmintenset trap_raz_wi +#define access_pmintenclr trap_raz_wi /* Architected CP15 registers. * CRn denotes the primary register number, but is copied to the CRm in the @@ -405,6 +405,9 @@ static const struct coproc_reg cp15_regs[] = { { CRn(12), CRm( 0), Op1( 0), Op2( 0), is32, NULL, reset_val, c12_VBAR, 0x00000000 }, + /* ICC_SRE */ + { CRn(12), CRm(12), Op1( 0), Op2( 5), is32, trap_raz_wi }, + /* CONTEXTIDR/TPIDRURW/TPIDRURO/TPIDRPRW: swapped by interrupt.S. */ { CRn(13), CRm( 0), Op1( 0), Op2( 1), is32, access_vm_reg, reset_val, c13_CID, 0x00000000 }, diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 4cc3b719208e..8f81945c4365 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -424,6 +424,11 @@ static const struct sys_reg_desc sys_reg_descs[] = { /* VBAR_EL1 */ { Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b0000), Op2(0b000), NULL, reset_val, VBAR_EL1, 0 }, + + /* ICC_SRE_EL1 */ + { Op0(0b11), Op1(0b000), CRn(0b1100), CRm(0b1100), Op2(0b101), + trap_raz_wi }, + /* CONTEXTIDR_EL1 */ { Op0(0b11), Op1(0b000), CRn(0b1101), CRm(0b0000), Op2(0b001), access_vm_reg, reset_val, CONTEXTIDR_EL1, 0 }, -- 1.8.3.2