aboutsummaryrefslogtreecommitdiff
path: root/arch/arm64
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2020-01-31 09:30:41 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-01-31 09:30:41 -0800
commite813e65038389b66d2f8dd87588694caf8dc2923 (patch)
tree4595d8ebaf672b79b412bd663a13907fd785478d /arch/arm64
parentccaaaf6fe5a5e1fffca5cca0f3fc4ec84d7ae752 (diff)
parent4cbc418a44d5067133271bb6eeac2382f2bf94f7 (diff)
downloadkernel-e813e65038389b66d2f8dd87588694caf8dc2923.tar.gz
Merge tag 'kvm-5.6-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini: "This is the first batch of KVM changes. ARM: - cleanups and corner case fixes. PPC: - Bugfixes x86: - Support for mapping DAX areas with large nested page table entries. - Cleanups and bugfixes here too. A particularly important one is a fix for FPU load when the thread has TIF_NEED_FPU_LOAD. There is also a race condition which could be used in guest userspace to exploit the guest kernel, for which the embargo expired today. - Fast path for IPI delivery vmexits, shaving about 200 clock cycles from IPI latency. - Protect against "Spectre-v1/L1TF" (bring data in the cache via speculative out of bound accesses, use L1TF on the sibling hyperthread to read it), which unfortunately is an even bigger whack-a-mole game than SpectreV1. Sean continues his mission to rewrite KVM. In addition to a sizable number of x86 patches, this time he contributed a pretty large refactoring of vCPU creation that affects all architectures but should not have any visible effect. s390 will come next week together with some more x86 patches" * tag 'kvm-5.6-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (204 commits) x86/KVM: Clean up host's steal time structure x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is not missed x86/kvm: Cache gfn to pfn translation x86/kvm: Introduce kvm_(un)map_gfn() x86/kvm: Be careful not to clear KVM_VCPU_FLUSH_TLB bit KVM: PPC: Book3S PR: Fix -Werror=return-type build failure KVM: PPC: Book3S HV: Release lock on page-out failure path KVM: arm64: Treat emulated TVAL TimerValue as a signed 32-bit integer KVM: arm64: pmu: Only handle supported event counters KVM: arm64: pmu: Fix chained SW_INCR counters KVM: arm64: pmu: Don't mark a counter as chained if the odd one is disabled KVM: arm64: pmu: Don't increment SW_INCR if PMCR.E is unset KVM: x86: Use a typedef for fastop functions KVM: X86: Add 'else' to unify fastop and execute call path KVM: x86: inline memslot_valid_for_gpte KVM: x86/mmu: Use huge pages for DAX-backed files KVM: x86/mmu: Remove lpage_is_disallowed() check from set_spte() KVM: x86/mmu: Fold max_mapping_level() into kvm_mmu_hugepage_adjust() KVM: x86/mmu: Zap any compound page when collapsing sptes KVM: x86/mmu: Remove obsolete gfn restoration in FNAME(fetch) ...
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/include/asm/kvm_emulate.h40
-rw-r--r--arch/arm64/include/asm/kvm_host.h16
-rw-r--r--arch/arm64/include/asm/kvm_mmio.h29
-rw-r--r--arch/arm64/include/asm/ptrace.h1
-rw-r--r--arch/arm64/include/uapi/asm/kvm.h12
-rw-r--r--arch/arm64/include/uapi/asm/ptrace.h1
-rw-r--r--arch/arm64/kvm/guest.c5
-rw-r--r--arch/arm64/kvm/hyp/entry.S7
-rw-r--r--arch/arm64/kvm/inject_fault.c70
-rw-r--r--arch/arm64/kvm/reset.c2
-rw-r--r--arch/arm64/kvm/va_layout.c56
11 files changed, 153 insertions, 86 deletions
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 5efe5ca8fecf..688c63412cc2 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -17,7 +17,6 @@
#include <asm/esr.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_hyp.h>
-#include <asm/kvm_mmio.h>
#include <asm/ptrace.h>
#include <asm/cputype.h>
#include <asm/virt.h>
@@ -219,6 +218,38 @@ static inline void vcpu_write_spsr(struct kvm_vcpu *vcpu, unsigned long v)
vcpu_gp_regs(vcpu)->spsr[KVM_SPSR_EL1] = v;
}
+/*
+ * The layout of SPSR for an AArch32 state is different when observed from an
+ * AArch64 SPSR_ELx or an AArch32 SPSR_*. This function generates the AArch32
+ * view given an AArch64 view.
+ *
+ * In ARM DDI 0487E.a see:
+ *
+ * - The AArch64 view (SPSR_EL2) in section C5.2.18, page C5-426
+ * - The AArch32 view (SPSR_abt) in section G8.2.126, page G8-6256
+ * - The AArch32 view (SPSR_und) in section G8.2.132, page G8-6280
+ *
+ * Which show the following differences:
+ *
+ * | Bit | AA64 | AA32 | Notes |
+ * +-----+------+------+-----------------------------|
+ * | 24 | DIT | J | J is RES0 in ARMv8 |
+ * | 21 | SS | DIT | SS doesn't exist in AArch32 |
+ *
+ * ... and all other bits are (currently) common.
+ */
+static inline unsigned long host_spsr_to_spsr32(unsigned long spsr)
+{
+ const unsigned long overlap = BIT(24) | BIT(21);
+ unsigned long dit = !!(spsr & PSR_AA32_DIT_BIT);
+
+ spsr &= ~overlap;
+
+ spsr |= dit << 21;
+
+ return spsr;
+}
+
static inline bool vcpu_mode_priv(const struct kvm_vcpu *vcpu)
{
u32 mode;
@@ -283,6 +314,11 @@ static inline bool kvm_vcpu_dabt_issext(const struct kvm_vcpu *vcpu)
return !!(kvm_vcpu_get_hsr(vcpu) & ESR_ELx_SSE);
}
+static inline bool kvm_vcpu_dabt_issf(const struct kvm_vcpu *vcpu)
+{
+ return !!(kvm_vcpu_get_hsr(vcpu) & ESR_ELx_SF);
+}
+
static inline int kvm_vcpu_dabt_get_rd(const struct kvm_vcpu *vcpu)
{
return (kvm_vcpu_get_hsr(vcpu) & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT;
@@ -304,7 +340,7 @@ static inline bool kvm_vcpu_dabt_is_cm(const struct kvm_vcpu *vcpu)
return !!(kvm_vcpu_get_hsr(vcpu) & ESR_ELx_CM);
}
-static inline int kvm_vcpu_dabt_get_as(const struct kvm_vcpu *vcpu)
+static inline unsigned int kvm_vcpu_dabt_get_as(const struct kvm_vcpu *vcpu)
{
return 1 << ((kvm_vcpu_get_hsr(vcpu) & ESR_ELx_SAS) >> ESR_ELx_SAS_SHIFT);
}
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index f5acdde17f3b..d87aa609d2b6 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -24,7 +24,6 @@
#include <asm/fpsimd.h>
#include <asm/kvm.h>
#include <asm/kvm_asm.h>
-#include <asm/kvm_mmio.h>
#include <asm/thread_info.h>
#define __KVM_HAVE_ARCH_INTC_INITIALIZED
@@ -53,7 +52,7 @@ int kvm_arm_init_sve(void);
int __attribute_const__ kvm_target_cpu(void);
int kvm_reset_vcpu(struct kvm_vcpu *vcpu);
-void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu);
+void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu);
int kvm_arch_vm_ioctl_check_extension(struct kvm *kvm, long ext);
void __extended_idmap_trampoline(phys_addr_t boot_pgd, phys_addr_t idmap_start);
@@ -325,9 +324,6 @@ struct kvm_vcpu_arch {
/* Don't run the guest (internal implementation need) */
bool pause;
- /* IO related fields */
- struct kvm_decode mmio_decode;
-
/* Cache some mmu pages needed inside spinlock regions */
struct kvm_mmu_memory_cache mmu_page_cache;
@@ -446,8 +442,6 @@ int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);
int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end);
int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
-struct kvm_vcpu *kvm_arm_get_running_vcpu(void);
-struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void);
void kvm_arm_halt_guest(struct kvm *kvm);
void kvm_arm_resume_guest(struct kvm *kvm);
@@ -491,6 +485,14 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
void handle_exit_early(struct kvm_vcpu *vcpu, struct kvm_run *run,
int exception_index);
+/* MMIO helpers */
+void kvm_mmio_write_buf(void *buf, unsigned int len, unsigned long data);
+unsigned long kvm_mmio_read_buf(const void *buf, unsigned int len);
+
+int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run);
+int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
+ phys_addr_t fault_ipa);
+
int kvm_perf_init(void);
int kvm_perf_teardown(void);
diff --git a/arch/arm64/include/asm/kvm_mmio.h b/arch/arm64/include/asm/kvm_mmio.h
deleted file mode 100644
index 02b5c48fd467..000000000000
--- a/arch/arm64/include/asm/kvm_mmio.h
+++ /dev/null
@@ -1,29 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2012 - Virtual Open Systems and Columbia University
- * Author: Christoffer Dall <c.dall@virtualopensystems.com>
- */
-
-#ifndef __ARM64_KVM_MMIO_H__
-#define __ARM64_KVM_MMIO_H__
-
-#include <linux/kvm_host.h>
-#include <asm/kvm_arm.h>
-
-/*
- * This is annoying. The mmio code requires this, even if we don't
- * need any decoding. To be fixed.
- */
-struct kvm_decode {
- unsigned long rt;
- bool sign_extend;
-};
-
-void kvm_mmio_write_buf(void *buf, unsigned int len, unsigned long data);
-unsigned long kvm_mmio_read_buf(const void *buf, unsigned int len);
-
-int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run);
-int io_mem_abort(struct kvm_vcpu *vcpu, struct kvm_run *run,
- phys_addr_t fault_ipa);
-
-#endif /* __ARM64_KVM_MMIO_H__ */
diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index fbebb411ae20..bf57308fcd63 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -62,6 +62,7 @@
#define PSR_AA32_I_BIT 0x00000080
#define PSR_AA32_A_BIT 0x00000100
#define PSR_AA32_E_BIT 0x00000200
+#define PSR_AA32_PAN_BIT 0x00400000
#define PSR_AA32_SSBS_BIT 0x00800000
#define PSR_AA32_DIT_BIT 0x01000000
#define PSR_AA32_Q_BIT 0x08000000
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 820e5751ada7..ba85bb23f060 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -220,10 +220,18 @@ struct kvm_vcpu_events {
#define KVM_REG_ARM_PTIMER_CVAL ARM64_SYS_REG(3, 3, 14, 2, 2)
#define KVM_REG_ARM_PTIMER_CNT ARM64_SYS_REG(3, 3, 14, 0, 1)
-/* EL0 Virtual Timer Registers */
+/*
+ * EL0 Virtual Timer Registers
+ *
+ * WARNING:
+ * KVM_REG_ARM_TIMER_CVAL and KVM_REG_ARM_TIMER_CNT are not defined
+ * with the appropriate register encodings. Their values have been
+ * accidentally swapped. As this is set API, the definitions here
+ * must be used, rather than ones derived from the encodings.
+ */
#define KVM_REG_ARM_TIMER_CTL ARM64_SYS_REG(3, 3, 14, 3, 1)
-#define KVM_REG_ARM_TIMER_CNT ARM64_SYS_REG(3, 3, 14, 3, 2)
#define KVM_REG_ARM_TIMER_CVAL ARM64_SYS_REG(3, 3, 14, 0, 2)
+#define KVM_REG_ARM_TIMER_CNT ARM64_SYS_REG(3, 3, 14, 3, 2)
/* KVM-as-firmware specific pseudo-registers */
#define KVM_REG_ARM_FW (0x0014 << KVM_REG_ARM_COPROC_SHIFT)
diff --git a/arch/arm64/include/uapi/asm/ptrace.h b/arch/arm64/include/uapi/asm/ptrace.h
index 7ed9294e2004..d1bb5b69f1ce 100644
--- a/arch/arm64/include/uapi/asm/ptrace.h
+++ b/arch/arm64/include/uapi/asm/ptrace.h
@@ -49,6 +49,7 @@
#define PSR_SSBS_BIT 0x00001000
#define PSR_PAN_BIT 0x00400000
#define PSR_UAO_BIT 0x00800000
+#define PSR_DIT_BIT 0x01000000
#define PSR_V_BIT 0x10000000
#define PSR_C_BIT 0x20000000
#define PSR_Z_BIT 0x40000000
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 2fff06114a8f..2bd92301d32f 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -47,11 +47,6 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
{ NULL }
};
-int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
-{
- return 0;
-}
-
static bool core_reg_offset_is_vreg(u64 off)
{
return off >= KVM_REG_ARM_CORE_REG(fp_regs.vregs) &&
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S
index 0c6832ec52b1..d22d0534dd60 100644
--- a/arch/arm64/kvm/hyp/entry.S
+++ b/arch/arm64/kvm/hyp/entry.S
@@ -51,7 +51,7 @@
* u64 __guest_enter(struct kvm_vcpu *vcpu,
* struct kvm_cpu_context *host_ctxt);
*/
-ENTRY(__guest_enter)
+SYM_FUNC_START(__guest_enter)
// x0: vcpu
// x1: host context
// x2-x17: clobbered by macros
@@ -100,9 +100,8 @@ alternative_else_nop_endif
// Do not touch any register after this!
eret
sb
-ENDPROC(__guest_enter)
-ENTRY(__guest_exit)
+SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL)
// x0: return code
// x1: vcpu
// x2-x29,lr: vcpu regs
@@ -195,4 +194,4 @@ abort_guest_exit_end:
msr spsr_el2, x4
orr x0, x0, x5
1: ret
-ENDPROC(__guest_exit)
+SYM_FUNC_END(__guest_enter)
diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
index ccdb6a051ab2..6aafc2825c1c 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c
@@ -14,9 +14,6 @@
#include <asm/kvm_emulate.h>
#include <asm/esr.h>
-#define PSTATE_FAULT_BITS_64 (PSR_MODE_EL1h | PSR_A_BIT | PSR_F_BIT | \
- PSR_I_BIT | PSR_D_BIT)
-
#define CURRENT_EL_SP_EL0_VECTOR 0x0
#define CURRENT_EL_SP_ELx_VECTOR 0x200
#define LOWER_EL_AArch64_VECTOR 0x400
@@ -50,6 +47,69 @@ static u64 get_except_vector(struct kvm_vcpu *vcpu, enum exception_type type)
return vcpu_read_sys_reg(vcpu, VBAR_EL1) + exc_offset + type;
}
+/*
+ * When an exception is taken, most PSTATE fields are left unchanged in the
+ * handler. However, some are explicitly overridden (e.g. M[4:0]). Luckily all
+ * of the inherited bits have the same position in the AArch64/AArch32 SPSR_ELx
+ * layouts, so we don't need to shuffle these for exceptions from AArch32 EL0.
+ *
+ * For the SPSR_ELx layout for AArch64, see ARM DDI 0487E.a page C5-429.
+ * For the SPSR_ELx layout for AArch32, see ARM DDI 0487E.a page C5-426.
+ *
+ * Here we manipulate the fields in order of the AArch64 SPSR_ELx layout, from
+ * MSB to LSB.
+ */
+static unsigned long get_except64_pstate(struct kvm_vcpu *vcpu)
+{
+ unsigned long sctlr = vcpu_read_sys_reg(vcpu, SCTLR_EL1);
+ unsigned long old, new;
+
+ old = *vcpu_cpsr(vcpu);
+ new = 0;
+
+ new |= (old & PSR_N_BIT);
+ new |= (old & PSR_Z_BIT);
+ new |= (old & PSR_C_BIT);
+ new |= (old & PSR_V_BIT);
+
+ // TODO: TCO (if/when ARMv8.5-MemTag is exposed to guests)
+
+ new |= (old & PSR_DIT_BIT);
+
+ // PSTATE.UAO is set to zero upon any exception to AArch64
+ // See ARM DDI 0487E.a, page D5-2579.
+
+ // PSTATE.PAN is unchanged unless SCTLR_ELx.SPAN == 0b0
+ // SCTLR_ELx.SPAN is RES1 when ARMv8.1-PAN is not implemented
+ // See ARM DDI 0487E.a, page D5-2578.
+ new |= (old & PSR_PAN_BIT);
+ if (!(sctlr & SCTLR_EL1_SPAN))
+ new |= PSR_PAN_BIT;
+
+ // PSTATE.SS is set to zero upon any exception to AArch64
+ // See ARM DDI 0487E.a, page D2-2452.
+
+ // PSTATE.IL is set to zero upon any exception to AArch64
+ // See ARM DDI 0487E.a, page D1-2306.
+
+ // PSTATE.SSBS is set to SCTLR_ELx.DSSBS upon any exception to AArch64
+ // See ARM DDI 0487E.a, page D13-3258
+ if (sctlr & SCTLR_ELx_DSSBS)
+ new |= PSR_SSBS_BIT;
+
+ // PSTATE.BTYPE is set to zero upon any exception to AArch64
+ // See ARM DDI 0487E.a, pages D1-2293 to D1-2294.
+
+ new |= PSR_D_BIT;
+ new |= PSR_A_BIT;
+ new |= PSR_I_BIT;
+ new |= PSR_F_BIT;
+
+ new |= PSR_MODE_EL1h;
+
+ return new;
+}
+
static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr)
{
unsigned long cpsr = *vcpu_cpsr(vcpu);
@@ -59,7 +119,7 @@ static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr
vcpu_write_elr_el1(vcpu, *vcpu_pc(vcpu));
*vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync);
- *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
+ *vcpu_cpsr(vcpu) = get_except64_pstate(vcpu);
vcpu_write_spsr(vcpu, cpsr);
vcpu_write_sys_reg(vcpu, addr, FAR_EL1);
@@ -94,7 +154,7 @@ static void inject_undef64(struct kvm_vcpu *vcpu)
vcpu_write_elr_el1(vcpu, *vcpu_pc(vcpu));
*vcpu_pc(vcpu) = get_except_vector(vcpu, except_type_sync);
- *vcpu_cpsr(vcpu) = PSTATE_FAULT_BITS_64;
+ *vcpu_cpsr(vcpu) = get_except64_pstate(vcpu);
vcpu_write_spsr(vcpu, cpsr);
/*
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index f4a8ae918827..30b7ea680f66 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -204,7 +204,7 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu)
return true;
}
-void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu)
+void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu)
{
kfree(vcpu->arch.sve_state);
}
diff --git a/arch/arm64/kvm/va_layout.c b/arch/arm64/kvm/va_layout.c
index dab1fea4752a..a4f48c1ac28c 100644
--- a/arch/arm64/kvm/va_layout.c
+++ b/arch/arm64/kvm/va_layout.c
@@ -13,52 +13,46 @@
#include <asm/kvm_mmu.h>
/*
- * The LSB of the random hyp VA tag or 0 if no randomization is used.
+ * The LSB of the HYP VA tag
*/
static u8 tag_lsb;
/*
- * The random hyp VA tag value with the region bit if hyp randomization is used
+ * The HYP VA tag value with the region bit
*/
static u64 tag_val;
static u64 va_mask;
+/*
+ * We want to generate a hyp VA with the following format (with V ==
+ * vabits_actual):
+ *
+ * 63 ... V | V-1 | V-2 .. tag_lsb | tag_lsb - 1 .. 0
+ * ---------------------------------------------------------
+ * | 0000000 | hyp_va_msb | random tag | kern linear VA |
+ * |--------- tag_val -----------|----- va_mask ---|
+ *
+ * which does not conflict with the idmap regions.
+ */
__init void kvm_compute_layout(void)
{
phys_addr_t idmap_addr = __pa_symbol(__hyp_idmap_text_start);
u64 hyp_va_msb;
- int kva_msb;
/* Where is my RAM region? */
hyp_va_msb = idmap_addr & BIT(vabits_actual - 1);
hyp_va_msb ^= BIT(vabits_actual - 1);
- kva_msb = fls64((u64)phys_to_virt(memblock_start_of_DRAM()) ^
+ tag_lsb = fls64((u64)phys_to_virt(memblock_start_of_DRAM()) ^
(u64)(high_memory - 1));
- if (kva_msb == (vabits_actual - 1)) {
- /*
- * No space in the address, let's compute the mask so
- * that it covers (vabits_actual - 1) bits, and the region
- * bit. The tag stays set to zero.
- */
- va_mask = BIT(vabits_actual - 1) - 1;
- va_mask |= hyp_va_msb;
- } else {
- /*
- * We do have some free bits to insert a random tag.
- * Hyp VAs are now created from kernel linear map VAs
- * using the following formula (with V == vabits_actual):
- *
- * 63 ... V | V-1 | V-2 .. tag_lsb | tag_lsb - 1 .. 0
- * ---------------------------------------------------------
- * | 0000000 | hyp_va_msb | random tag | kern linear VA |
- */
- tag_lsb = kva_msb;
- va_mask = GENMASK_ULL(tag_lsb - 1, 0);
- tag_val = get_random_long() & GENMASK_ULL(vabits_actual - 2, tag_lsb);
- tag_val |= hyp_va_msb;
- tag_val >>= tag_lsb;
+ va_mask = GENMASK_ULL(tag_lsb - 1, 0);
+ tag_val = hyp_va_msb;
+
+ if (tag_lsb != (vabits_actual - 1)) {
+ /* We have some free bits to insert a random tag. */
+ tag_val |= get_random_long() & GENMASK_ULL(vabits_actual - 2, tag_lsb);
}
+ tag_val >>= tag_lsb;
}
static u32 compute_instruction(int n, u32 rd, u32 rn)
@@ -117,11 +111,11 @@ void __init kvm_update_va_mask(struct alt_instr *alt,
* VHE doesn't need any address translation, let's NOP
* everything.
*
- * Alternatively, if we don't have any spare bits in
- * the address, NOP everything after masking that
- * kernel VA.
+ * Alternatively, if the tag is zero (because the layout
+ * dictates it and we don't have any spare bits in the
+ * address), NOP everything after masking the kernel VA.
*/
- if (has_vhe() || (!tag_lsb && i > 0)) {
+ if (has_vhe() || (!tag_val && i > 0)) {
updptr[i] = cpu_to_le32(aarch64_insn_gen_nop());
continue;
}