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Date:   Tue,  3 May 2022 06:02:04 +0000
From:   Oliver Upton <oupton@...gle.com>
To:     kvmarm@...ts.cs.columbia.edu
Cc:     kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, maz@...nel.org, james.morse@....com,
        alexandru.elisei@....com, suzuki.poulose@....com,
        reijiw@...gle.com, ricarkol@...gle.com,
        Oliver Upton <oupton@...gle.com>
Subject: [PATCH v4 6/7] KVM/arm64: Hide AArch32 PMU registers when not available

From: Alexandru Elisei <alexandru.elisei@....com>

commit 11663111cd49 ("KVM: arm64: Hide PMU registers from userspace when
not available") hid the AArch64 PMU registers from userspace and guest
when the PMU VCPU feature was not set. Do the same when the PMU
registers are accessed by an AArch32 guest. While we're at it, rename
the previously unused AA32_ZEROHIGH to AA32_DIRECT to match the behavior
of get_access_mask().

Now that KVM emulates ID_DFR0 and hides the PMU from the guest when the
feature is not set, it is safe to inject to inject an undefined exception
when the PMU is not present, as that corresponds to the architected
behaviour.

Signed-off-by: Alexandru Elisei <alexandru.elisei@....com>
[Oliver - Add AA32_DIRECT to match the zero value of the enum]
Signed-off-by: Oliver Upton <oupton@...gle.com>
---
 arch/arm64/kvm/sys_regs.c | 60 ++++++++++++++++++++-------------------
 arch/arm64/kvm/sys_regs.h |  2 +-
 2 files changed, 32 insertions(+), 30 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 586b292ca94f..f3235eafdadc 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2014,20 +2014,22 @@ static const struct sys_reg_desc cp14_64_regs[] = {
 	{ Op1( 0), CRm( 2), .access = trap_raz_wi },
 };
 
+#define CP15_PMU_SYS_REG(_map, _Op1, _CRn, _CRm, _Op2)			\
+	AA32(_map),							\
+	Op1(_Op1), CRn(_CRn), CRm(_CRm), Op2(_Op2),			\
+	.visibility = pmu_visibility
+
 /* Macro to expand the PMEVCNTRn register */
 #define PMU_PMEVCNTR(n)							\
-	/* PMEVCNTRn */							\
-	{ Op1(0), CRn(0b1110),						\
-	  CRm((0b1000 | (((n) >> 3) & 0x3))), Op2(((n) & 0x7)),		\
-	  access_pmu_evcntr }
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 0b1110,				\
+	  (0b1000 | (((n) >> 3) & 0x3)), ((n) & 0x7)),			\
+	  .access = access_pmu_evcntr }
 
 /* Macro to expand the PMEVTYPERn register */
 #define PMU_PMEVTYPER(n)						\
-	/* PMEVTYPERn */						\
-	{ Op1(0), CRn(0b1110),						\
-	  CRm((0b1100 | (((n) >> 3) & 0x3))), Op2(((n) & 0x7)),		\
-	  access_pmu_evtyper }
-
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 0b1110,				\
+	  (0b1100 | (((n) >> 3) & 0x3)), ((n) & 0x7)),			\
+	  .access = access_pmu_evtyper }
 /*
  * Trapped cp15 registers. TTBR0/TTBR1 get a double encoding,
  * depending on the way they are accessed (as a 32bit or a 64bit
@@ -2067,25 +2069,25 @@ static const struct sys_reg_desc cp15_regs[] = {
 	{ Op1( 0), CRn( 7), CRm(14), Op2( 2), access_dcsw },
 
 	/* PMU */
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 0), access_pmcr },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 1), access_pmcnten },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 2), access_pmcnten },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 3), access_pmovs },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 4), access_pmswinc },
-	{ Op1( 0), CRn( 9), CRm(12), Op2( 5), access_pmselr },
-	{ AA32(LO), Op1( 0), CRn( 9), CRm(12), Op2( 6), access_pmceid },
-	{ AA32(LO), Op1( 0), CRn( 9), CRm(12), Op2( 7), access_pmceid },
-	{ Op1( 0), CRn( 9), CRm(13), Op2( 0), access_pmu_evcntr },
-	{ Op1( 0), CRn( 9), CRm(13), Op2( 1), access_pmu_evtyper },
-	{ Op1( 0), CRn( 9), CRm(13), Op2( 2), access_pmu_evcntr },
-	{ Op1( 0), CRn( 9), CRm(14), Op2( 0), access_pmuserenr },
-	{ Op1( 0), CRn( 9), CRm(14), Op2( 1), access_pminten },
-	{ Op1( 0), CRn( 9), CRm(14), Op2( 2), access_pminten },
-	{ Op1( 0), CRn( 9), CRm(14), Op2( 3), access_pmovs },
-	{ AA32(HI), Op1( 0), CRn( 9), CRm(14), Op2( 4), access_pmceid },
-	{ AA32(HI), Op1( 0), CRn( 9), CRm(14), Op2( 5), access_pmceid },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 12, 0), .access = access_pmcr },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 12, 1), .access = access_pmcnten },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 12, 2), .access = access_pmcnten },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 12, 3), .access = access_pmovs },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 12, 4), .access = access_pmswinc },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 12, 5), .access = access_pmselr },
+	{ CP15_PMU_SYS_REG(LO,     0, 9, 12, 6), .access = access_pmceid },
+	{ CP15_PMU_SYS_REG(LO,     0, 9, 12, 7), .access = access_pmceid },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 13, 0), .access = access_pmu_evcntr },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 13, 1), .access = access_pmu_evtyper },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 13, 2), .access = access_pmu_evcntr },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 14, 0), .access = access_pmuserenr },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 14, 1), .access = access_pminten },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 14, 2), .access = access_pminten },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 14, 3), .access = access_pmovs },
+	{ CP15_PMU_SYS_REG(HI,     0, 9, 14, 4), .access = access_pmceid },
+	{ CP15_PMU_SYS_REG(HI,     0, 9, 14, 5), .access = access_pmceid },
 	/* PMMIR */
-	{ Op1( 0), CRn( 9), CRm(14), Op2( 6), trap_raz_wi },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 9, 14, 6), .access = trap_raz_wi },
 
 	/* PRRR/MAIR0 */
 	{ AA32(LO), Op1( 0), CRn(10), CRm( 2), Op2( 0), access_vm_reg, NULL, MAIR_EL1 },
@@ -2170,7 +2172,7 @@ static const struct sys_reg_desc cp15_regs[] = {
 	PMU_PMEVTYPER(29),
 	PMU_PMEVTYPER(30),
 	/* PMCCFILTR */
-	{ Op1(0), CRn(14), CRm(15), Op2(7), access_pmu_evtyper },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 14, 15, 7), .access = access_pmu_evtyper },
 
 	{ Op1(1), CRn( 0), CRm( 0), Op2(0), access_ccsidr },
 	{ Op1(1), CRn( 0), CRm( 0), Op2(1), access_clidr },
@@ -2179,7 +2181,7 @@ static const struct sys_reg_desc cp15_regs[] = {
 
 static const struct sys_reg_desc cp15_64_regs[] = {
 	{ Op1( 0), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, TTBR0_EL1 },
-	{ Op1( 0), CRn( 0), CRm( 9), Op2( 0), access_pmu_evcntr },
+	{ CP15_PMU_SYS_REG(DIRECT, 0, 0, 9, 0), .access = access_pmu_evcntr },
 	{ Op1( 0), CRn( 0), CRm(12), Op2( 0), access_gic_sgi }, /* ICC_SGI1R */
 	{ Op1( 1), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, TTBR1_EL1 },
 	{ Op1( 1), CRn( 0), CRm(12), Op2( 0), access_gic_sgi }, /* ICC_ASGI1R */
diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
index 0d31a12b640c..aee8ea054f0d 100644
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -47,7 +47,7 @@ struct sys_reg_desc {
 	const char *name;
 
 	enum {
-		AA32_ZEROHIGH,
+		AA32_DIRECT,
 		AA32_LO,
 		AA32_HI,
 	} aarch32_map;
-- 
2.36.0.464.gb9c8b46e94-goog

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