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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v2 09/39] xen/riscv: implement virtual APLIC MMIO emulation
> Guests running under Xen program interrupt routing by writing to APLIC
> MMIO registers. Xen must intercept these accesses to enforce interrupt
> isolation between domains and to translate guest routing intent into the
> underlying physical MSI topology.
>
> Writes are gated by the domain's authorised interrupt bitmap so that a
> guest cannot affect interrupts it does not own. TARGET register writes
> additionally require translation of the hart and IMSIC guest-file
> indices from virtual to physical, as the APLIC uses these fields
> directly to compute the MSI delivery address.
>
> Delegation (APLIC_SOURCECFG_D) is not yet supported.
>
> Co-developed-by: Romain Caritey <Romain.Caritey@xxxxxxxxxxxxx>
> Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
>
> diff --git a/xen/arch/riscv/aplic-priv.h b/xen/arch/riscv/aplic-priv.h
> index 35100d3a64..b3a1f79c5b 100644
> --- a/xen/arch/riscv/aplic-priv.h
> +++ b/xen/arch/riscv/aplic-priv.h
> @@ -47,4 +47,7 @@ struct aplic_priv {
> */
> extern unsigned int guest_aplic_num_sources;
>
> +uint32_t aplic_msi_target_gen(const struct vcpu *target_vcpu,
> + uint32_t base_val);
> +
> #endif /* ASM_RISCV_APLIC_PRIV_H */
> diff --git a/xen/arch/riscv/aplic.c b/xen/arch/riscv/aplic.c
> index 3681f0669e..66ba4986a9 100644
> --- a/xen/arch/riscv/aplic.c
> +++ b/xen/arch/riscv/aplic.c
> @@ -16,6 +16,7 @@
> #include <xen/irq.h>
> #include <xen/mm.h>
> #include <xen/sections.h>
> +#include <xen/sched.h>
> #include <xen/spinlock.h>
> #include <xen/types.h>
> #include <xen/vmap.h>
> @@ -28,8 +29,6 @@
> #include <asm/io.h>
> #include <asm/riscv_encoding.h>
>
> -#define APLIC_DEFAULT_PRIORITY 1
> -
> static struct aplic_priv aplic = {
> .lock = SPIN_LOCK_UNLOCKED,
> };
> @@ -38,6 +37,127 @@ static struct intc_info __ro_after_init aplic_info = {
> .hw_variant = INTC_APLIC,
> };
>
> +/*
> + * The arrangement of IMSIC interrupt files in MMIO space follows a topology
> + * defined by the RISC-V AIA specification. An IMSIC group is a set of
> + * interrupt files (e.g., in a cluster or socket) co-located in memory.
> + *
> + * The physical address of an outgoing MSI is calculated by bitwise ORing a
> + * Base Physical Page Number (Base PPN) with the Group Index (g), the Hart
> + * Index (h) and, for a supervisor-level interrupt domain, the Guest Index:
> + *
> + * ( Base PPN | (g << (HHXS + 12)) | (h << LHXS) | guest ) << 12
> + *
> + * where Base PPN, HHXS, LHXS, HHXW and LHXW come from the {m,s}msiaddrcfg[h]
> + * registers of the interrupt domain that sends the MSI:
> + *
> + * XLEN-1 HHXS+24 LHXS+12 12 0
> + * | | | | |
> + * ------------------------------------------------------------
> + * |xxxx| g |xxxxxxxx| h |xxxx|Guest Index| 0 |
> + * ------------------------------------------------------------
> + *
> + * - g: group number.
> + * - h: hart number relative to the group.
> + * - xxxx: remaining Base PPN bits; each gap may be zero-width.
> + * - Guest Index: selects one of the 4 KiB pages right above the hart's own
> + * supervisor-level file, i.e. it starts at bit 12; LHXS must therefore be
> + * at least as large as the number of guest index bits.
> + * - Bits 11:0: always zero because IMSIC files are 4 KiB page-aligned.
> + *
> + * For wired interrupts in MSI delivery mode (domaincfg.DM = 1) the APLIC
> + * builds that address itself from the "Hart Index" field (bits 31:18) of the
> + * corresponding target[i] register. That field holds a hart index *number*,
> + * in which both indices are packed adjacently:
> + *
> + * 13 lhxw+hhxw lhxw 0
> + * | | | |
> + * ------------------------------------
> + * | 0 |Group Index|Hart Index|
> + * ------------------------------------
> + *
> + * - lhxw (Low Hart Index Width): the number of bits used for the hart number
> + * within a group.
> + * - hhxw (High Hart Index Width): the number of bits used for the group
> + * number; the remaining bits of the field must be zero.
> + *
> + * The Guest Index isn't a part of it: for a supervisor-level interrupt
> domain
> + * it has its own field (bits 17:12) in target[i].
> + *
> + * Because there are "xxxx" gaps (Base PPN bits) between the indices in the
> + * physical address (depending on HHXS and LHXS), software must extract the
> + * group and hart components separately and pack them into the APLIC-defined
> + * Hart Index format to ensure correct MSI targeting.
> + */
> +static unsigned long aplic_hart_field(unsigned int cpu)
> +{
> + const struct imsic_config *imsic = imsic_get_config();
> + const struct imsic_msi *msi = &imsic->msi[cpu];
> + /* Low Hart Index Shift */
> + unsigned int lhxs = imsic->guest_index_bits;
> + /* Low Hart Index Width */
> + unsigned int lhxw = imsic->hart_index_bits;
> + /* High Hart Index Width */
> + unsigned int hhxw = imsic->group_index_bits;
> + /* High Hart Index Shift */
> + unsigned int hhxs =
> + imsic->group_index_shift - APLIC_xMSICFGADDR_PPN_SHIFT * 2;
> + /*
> + * msi->base_addr is the base of the MMIO regset this CPU's interrupt
> + * files live in, and one regset can cover several harts; msi->offset
> + * selects this CPU's block inside it. The hart index bits are part of
> + * that offset, so both indexes have to be derived from the full address.
> + */
> + paddr_t target_addr = msi->base_addr + msi->offset;
> + unsigned long tppn = target_addr >> APLIC_xMSICFGADDR_PPN_SHIFT;
> + unsigned long g =
> + (tppn >> APLIC_xMSICFGADDR_PPN_HHX_SHIFT(hhxs)) &
> + APLIC_xMSICFGADDR_PPN_HHX_MASK(hhxw);
> + unsigned long h =
> + (tppn >> APLIC_xMSICFGADDR_PPN_LHX_SHIFT(lhxs)) &
> + APLIC_xMSICFGADDR_PPN_LHX_MASK(lhxw);
> +
> + return (g << lhxw) | h;
> +}
> +
> +uint32_t aplic_msi_target_gen(const struct vcpu *target_vcpu,
> + uint32_t base_val)
> +{
> + unsigned int guest_id = vcpu_guest_file_id(target_vcpu);
> + unsigned long hart_field = aplic_hart_field(target_vcpu->processor);
> +
> + base_val &= APLIC_TARGET_EIID;
> + base_val |= MASK_INSR(guest_id, APLIC_TARGET_GUEST_IDX);
> + base_val |= MASK_INSR(hart_field, APLIC_TARGET_HART_IDX);
> +
> + return base_val;
> +}
> +
> +uint32_t aplic_hw_read_reg(unsigned int offset)
> +{
> + unsigned long flags;
> + uint32_t val;
> +
> + ASSERT((offset < aplic.size) && IS_ALIGNED(offset, sizeof(uint32_t)));
> +
> + spin_lock_irqsave(&aplic.lock, flags);
> + val = readl((volatile void __iomem *)aplic.regs + offset);
> + spin_unlock_irqrestore(&aplic.lock, flags);
> +
> + return val;
> +}
> +
> +void aplic_hw_write_reg(unsigned int offset, uint32_t value)
> +{
> + unsigned long flags;
> +
> + ASSERT((offset < aplic.size) && IS_ALIGNED(offset, sizeof(uint32_t)));
> +
> + spin_lock_irqsave(&aplic.lock, flags);
> + writel(value, (volatile void __iomem *)aplic.regs + offset);
> + spin_unlock_irqrestore(&aplic.lock, flags);
> +}
> +
> static void __init aplic_init_hw_interrupts(void)
> {
> unsigned int i;
> @@ -53,9 +173,9 @@ static void __init aplic_init_hw_interrupts(void)
> /*
> * Low bits of target register contains Interrupt Priority bits which
> * can't be zero according to AIA spec.
> - * Thereby they are initialized to APLIC_DEFAULT_PRIORITY.
> + * Thereby they are initialized to APLIC_TARGET_IPRIO_DEFAULT.
> */
> - writel(APLIC_DEFAULT_PRIORITY, &aplic.regs->target[i]);
> + writel(APLIC_TARGET_IPRIO_DEFAULT, &aplic.regs->target[i]);
> }
>
> writel(APLIC_DOMAINCFG_IE | APLIC_DOMAINCFG_DM, &aplic.regs->domaincfg);
> diff --git a/xen/arch/riscv/include/asm/aplic.h
> b/xen/arch/riscv/include/asm/aplic.h
> index a2af55d54f..babba38607 100644
> --- a/xen/arch/riscv/include/asm/aplic.h
> +++ b/xen/arch/riscv/include/asm/aplic.h
> @@ -39,6 +39,13 @@
> #define APLIC_DOMAINCFG_IE BIT(8, U)
> #define APLIC_DOMAINCFG_DM BIT(2, U)
> #define APLIC_DOMAINCFG_BE BIT(0, U)
> +/*
> + * The bits a write may change. Everything else, including the read-only zero
> + * bit 7 and the reserved bits, has to read back as zero, and BE is WARL and
> + * hardwired to 0 as Xen is little-endian only.
> + */
> +#define APLIC_DOMAINCFG_WMASK (APLIC_DOMAINCFG_IE | \
> + APLIC_DOMAINCFG_DM)
>
> #define APLIC_SOURCECFG_BASE 0x0004
> #define APLIC_SOURCECFG_LAST 0x0ffc
> @@ -89,6 +96,9 @@
> #define APLIC_TARGET_GUEST_IDX GENMASK(17, 12)
> /* Bit 11 is reserved and reads as zero */
> #define APLIC_TARGET_EIID GENMASK(10, 0)
> +/* If target is in DM mode */
> +#define APLIC_TARGET_IPRIO GENMASK(7, 0)
> +#define APLIC_TARGET_IPRIO_DEFAULT 1U
>
> #define APLIC_IDC_SIZE 32
>
> @@ -98,6 +108,27 @@
> #define APLIC_SIZE(nr_cpus) \
> (APLIC_MIN_SIZE + APLIC_SIZE_ALIGN(APLIC_IDC_SIZE * (nr_cpus)))
>
> +/*
> + * Using setip is fine here, as all SET* and CLR* register groups consist of
> 32
> + * registers and therefore have identical sizes.
> + *
> + * Lowest 2 bits are always zero for SET* and CLR* registers.
> + */
> +#define APLIC_SETCLR_OFFSET_MASK \
> + (sizeof_field(struct aplic_regs, setip) - sizeof(uint32_t))
> +
> +#define APLIC_xMSICFGADDR_PPN_SHIFT IMSIC_MMIO_PAGE_SHIFT
> +
> +#define APLIC_xMSICFGADDR_PPN_HHX_MASK(hhxw) \
> + (BIT(hhxw, UL) - 1)
> +#define APLIC_xMSICFGADDR_PPN_HHX_SHIFT(hhxs) \
> + ((hhxs) + APLIC_xMSICFGADDR_PPN_SHIFT)
> +
> +#define APLIC_xMSICFGADDR_PPN_LHX_MASK(lhxw) \
> + (BIT(lhxw, UL) - 1)
> +#define APLIC_xMSICFGADDR_PPN_LHX_SHIFT(lhxs) \
> + (lhxs)
> +
> struct aplic_regs {
> uint32_t domaincfg; /* 0x0000 */
> uint32_t sourcecfg[1023]; /* 0x0004 */
> @@ -141,4 +172,7 @@ struct aplic_regs {
> uint32_t target[1023]; /* 0x3004 */
> };
>
> +uint32_t aplic_hw_read_reg(unsigned int offset);
> +void aplic_hw_write_reg(unsigned int offset, uint32_t value);
> +
> #endif /* ASM_RISCV_APLIC_H */
> diff --git a/xen/arch/riscv/include/asm/imsic.h
> b/xen/arch/riscv/include/asm/imsic.h
> index 2425430ed1..93f9e44c7d 100644
> --- a/xen/arch/riscv/include/asm/imsic.h
> +++ b/xen/arch/riscv/include/asm/imsic.h
> @@ -40,6 +40,19 @@ struct imsic_config {
> /* Base address */
> paddr_t base_addr;
>
> + /*
> + * MSI Target Address Scheme
> + *
> + * XLEN-1 HHXS+24 LHXS+12 12 0
> + * | | | | |
> + * ------------------------------------------------------------
> + * |xxxx| g |xxxxxxxx| h |xxxx|Guest Index| 0 |
> + * ------------------------------------------------------------
> + * - g: group number.
> + * - h: hart number relative to the group.
> + * - xxxx: remaining Base PPN bits; each gap may be zero-width.
> + */
> +
> /* Bits representing Guest index, HART index, and Group index */
> unsigned int guest_index_bits;
> unsigned int hart_index_bits;
> diff --git a/xen/arch/riscv/include/asm/vaplic.h
> b/xen/arch/riscv/include/asm/vaplic.h
> index 96080bfbc2..046c604915 100644
> --- a/xen/arch/riscv/include/asm/vaplic.h
> +++ b/xen/arch/riscv/include/asm/vaplic.h
> @@ -21,11 +21,16 @@ struct domain;
>
> struct vaplic_regs {
> uint32_t domaincfg;
> +
> + uint32_t *target;
> };
>
> struct vaplic {
> struct vintc vintc;
> struct vaplic_regs regs;
> +
> + paddr_t regs_start;
> + unsigned int regs_size;
> };
>
> int domain_vaplic_init(struct domain *d);
> diff --git a/xen/arch/riscv/vaplic.c b/xen/arch/riscv/vaplic.c
> index 14f6e3164a..8726f7203d 100644
> --- a/xen/arch/riscv/vaplic.c
> +++ b/xen/arch/riscv/vaplic.c
> @@ -17,6 +17,7 @@
> #include <asm/aia.h>
> #include <asm/imsic.h>
> #include <asm/intc.h>
> +#include <asm/mmio.h>
> #include <asm/vaplic.h>
>
> #include "aplic-priv.h"
> @@ -27,6 +28,279 @@ unsigned int __ro_after_init guest_aplic_num_sources;
>
> #define FDT_VAPLIC_INT_CELLS 2
>
> +#define AUTH_IRQ_BIT(d, irqn) \
> + (((irqn) < (d)->arch.vintc->nr_virqs) && \
> + test_bit(irqn, (d)->arch.vintc->used_irqs))
> +
> +/*
> + * Convert a byte offset (within a SETIP/CLRIP/SETIE/CLRIE register group) to
> + * a 32-bit word index into the used_irqs bitmap. Each word covers 32
> + * interrupt sources. For SOURCECFG and TARGET groups the same division also
> + * yields the interrupt number directly, because those arrays store one
> 32-bit
> + * register per source.
> + */
> +#define regoffset_to_word_idx(reg_val) ((reg_val) / sizeof(uint32_t))
> +
> +static uint32_t vaplic_target_read(const struct domain *d, unsigned int irqn)
> +{
> + const struct vaplic *vaplic = to_vaplic(d);
> +
> + /* target[0] doesn't exist so irqn == 0 should be impossible */
> + if ( !irqn || irqn >= vaplic->vintc.nr_virqs )
> + return 0;
> +
> + return read_atomic(&vaplic->regs.target[irqn]);
> +}
> +
> +static inline uint32_t generate_auth_mask(const struct domain *currd,
> + unsigned int word_idx)
> +{
> + unsigned int first_bit = word_idx * sizeof(uint32_t) * BITS_PER_BYTE;
> +
> + if ( word_idx >= DIV_ROUND_UP(currd->arch.vintc->nr_virqs,
> + sizeof(uint32_t) * BITS_PER_BYTE) )
> + {
> + gdprintk(XENLOG_DEBUG, "incorrect word_idx(%u) is passed\n",
> word_idx);
> +
> + return 0;
> + }
> +
> + return currd->arch.vintc->used_irqs[first_bit / BITS_PER_LONG] >>
> + (first_bit % BITS_PER_LONG);
> +}
> +
> +static bool vaplic_emulate_load(const struct vcpu *curr, paddr_t addr,
> + uint32_t *out)
> +{
> + const struct domain *currd = curr->domain;
> + const struct vaplic *vaplic = to_vaplic(currd);
> + const unsigned int offset = addr & APLIC_CTRL_REGION_OFFSET_MASK;
> + uint32_t auth_mask;
> + unsigned int i;
> +
> + ASSERT(curr == current);
> +
> + switch ( offset )
> + {
> + case APLIC_DOMAINCFG:
> + *out = vaplic->regs.domaincfg;
> +
> + return true;
> +
> + case APLIC_SETIPNUM:
> + case APLIC_SETIPNUM_LE:
> + case APLIC_CLRIPNUM:
> + case APLIC_SETIENUM:
> + case APLIC_CLRIENUM:
> + case APLIC_CLRIE_BASE ... APLIC_CLRIE_LAST:
> + /*
> + * Based on the RISC-V AIA spec a read of these registers
> + * always returns zero
> + */
> + *out = 0;
> +
> + return true;
> +
> + case APLIC_SETIP_BASE ... APLIC_SETIP_LAST:
> + case APLIC_CLRIP_BASE ... APLIC_CLRIP_LAST:
> + case APLIC_SETIE_BASE ... APLIC_SETIE_LAST:
> + i = regoffset_to_word_idx(offset & APLIC_SETCLR_OFFSET_MASK);
> + auth_mask = generate_auth_mask(currd, i);
> +
> + break;
> +
> + case APLIC_TARGET_BASE ... APLIC_TARGET_LAST:
> + /*
> + * As target registers start from 1:
> + * 0x3000 genmsi
> + * 0x3004 target[1]
> + * 0x3008 target[2]
> + * ...
> + * 0x3FFC target[1023]
> + * It is necessary to calculate an interrupt number by subtracting
> + * APLIC_GENMSI instead of APLIC_TARGET_BASE.
> + */
> + i = regoffset_to_word_idx(offset - APLIC_GENMSI);
> +
> + *out = AUTH_IRQ_BIT(currd, i) ? vaplic_target_read(currd, i) : 0;
> +
> + return true;
> +
> + default:
> + gdprintk(XENLOG_WARNING, "Unhandled APLIC read at offset %#x\n",
> + offset);
> +
> + return false;
> + }
> +
> + *out = aplic_hw_read_reg(offset) & auth_mask;
> +
> + return true;
> +}
> +
> +static bool vaplic_emulate_store(const struct vcpu *curr, paddr_t addr,
> + uint32_t value)
> +{
> + const struct domain *currd = curr->domain;
> + unsigned int offset = addr & APLIC_CTRL_REGION_OFFSET_MASK;
> +
> + ASSERT(curr == current);
> +
> + switch ( offset )
> + {
> + case APLIC_SETIP_BASE ... APLIC_SETIP_LAST:
> + case APLIC_CLRIP_BASE ... APLIC_CLRIP_LAST:
> + case APLIC_SETIE_BASE ... APLIC_SETIE_LAST:
> + case APLIC_CLRIE_BASE ... APLIC_CLRIE_LAST:
> + {
> + unsigned int word_idx =
> + regoffset_to_word_idx(offset & APLIC_SETCLR_OFFSET_MASK);
> +
> + value &= generate_auth_mask(currd, word_idx);
> +
> + break;
> + }
> +
> + case APLIC_SOURCECFG_BASE ... APLIC_SOURCECFG_LAST:
> + if ( value & APLIC_SOURCECFG_D )
> + {
> + dprintk(XENLOG_ERR, "APLIC_SOURCECFG_D isn't supported\n");
> +
> + goto fail;
> + }
> +
> + /*
> + * As sourcecfg register starts from 1:
> + * 0x0000 domaincfg
> + * 0x0004 sourcecfg[1]
> + * 0x0008 sourcecfg[2]
> + * ...
> + * 0x0FFC sourcecfg[1023]
> + * It is necessary to calculate an interrupt number by subtracting
> + * APLIC_DOMAINCFG instead of APLIC_SOURCECFG_BASE.
> + */
> + if ( !AUTH_IRQ_BIT(currd,
> + regoffset_to_word_idx(offset - APLIC_DOMAINCFG)) )
> + /* Interrupt not enabled, ignore it */
> + return true;
> +
> + if ( value > APLIC_SOURCECFG_SM_LEVEL_LOW )
This compares the whole value against 7, not the extracted SM field
(bits [2:0]). A perfectly legal SM=0 write with any bit set in the
reserved [9:3] range (e.g. value=8) gets rejected here even though the
actual field is fine Should be MASK_EXTR(value, APLIC_SOURCECFG_SM) >
APLIC_SOURCECFG_SM_LEVEL_LOW.
SM is WARL. If SM invalid but other fields valid, shouldn't reject whole
write. Instead override value.SM with current valid SM in this branch,
so other valid fields still get written.
> + {
> + gdprintk(XENLOG_ERR,
> + "value(%#x) is incorrect for sourcecfg register\n",
> + value);
> +
> + return true;
> + }
> +
> + break;
> +
> + case APLIC_TARGET_BASE ... APLIC_TARGET_LAST:
> + {
> + struct vaplic *vaplic = to_vaplic(currd);
> + struct vcpu *target_vcpu;
> + unsigned int guest_hart_idx = MASK_EXTR(value,
> APLIC_TARGET_HART_IDX);
> + /*
> + * Look at vaplic_emulate_load() for explanation why APLIC_GENMSI is
> + * subtracted.
> + */
> + unsigned int srcn = regoffset_to_word_idx(offset - APLIC_GENMSI);
> +
> + if ( !AUTH_IRQ_BIT(currd, srcn) )
> + /* Interrupt not enabled, ignore it */
> + return true;
> +
> + target_vcpu = domain_vcpu(currd, guest_hart_idx);
> +
> + if ( !target_vcpu )
> + {
> + dprintk(XENLOG_ERR, "Invalid vCPU id in target register\n");
> +
> + /* Ignore such writings */
> + return true;
> + }
> +
> + if ( vaplic->regs.domaincfg & APLIC_DOMAINCFG_DM )
> + {
> + /*
> + * A non-zero guest index asks for delivery to an interrupt file
> of
> + * nested guest. The vIMSIC node has no riscv,guest-index-bits
> + * property, so a guest is told its harts have no guest interrupt
> + * files and the field is read-only zero for them. The write
> isn't
> + * rejected (that would throw away a valid hart index and EIID);
> + * instead the field is dropped, which is also what
> + * aplic_msi_target_gen() does with it when programming the h/w.
> + */
> + if ( MASK_EXTR(value, APLIC_TARGET_GUEST_IDX) )
> + {
> + printk_once(XENLOG_WARNING
> + "%pd: vAPLIC target guest index != 0 is
> unsupported\n",
> + currd);
> +
> + /* Ignore such writes ... */
> + return true;
> + }
Comment above this says "The write isn't rejected ... instead the field
is dropped, which is also what aplic_msi_target_gen() does with it." But
the code doesn't follow it as it returns true immediately here before
the write occurred and without zeroing the guest index field.
> +
> + write_atomic(&vaplic->regs.target[srcn], value);
> +
> + value = aplic_msi_target_gen(target_vcpu, value);
> + }
> + else
> + {
> + /*
> + * IPRIO is WARL and zero isn't a legal value for it, so
> normalize
> + * it once: the guest then reads back exactly what it gets.
> + */
> + unsigned int iprio = MASK_EXTR(value, APLIC_TARGET_IPRIO) ?:
> + APLIC_TARGET_IPRIO_DEFAULT;
> + unsigned long h = cpuid_to_hartid(guest_hart_idx);
> +
> + value = MASK_INSR(guest_hart_idx, APLIC_TARGET_HART_IDX) |
> + MASK_INSR(iprio, APLIC_TARGET_IPRIO);
> +
> + write_atomic(&vaplic->regs.target[srcn], value);
> +
> + value = MASK_INSR(h, APLIC_TARGET_HART_IDX) |
> + MASK_INSR(iprio, APLIC_TARGET_IPRIO);
> + }
> +
> + break;
> + }
> +
> + case APLIC_SETIPNUM:
> + case APLIC_SETIPNUM_LE:
> + case APLIC_CLRIPNUM:
> + case APLIC_SETIENUM:
> + case APLIC_CLRIENUM:
> + if ( !value || !AUTH_IRQ_BIT(currd, value) )
> + return true;
> +
> + break;
> +
> + case APLIC_DOMAINCFG:
> + {
> + struct vaplic *vaplic = to_vaplic(currd);
> +
> + vaplic->regs.domaincfg = APLIC_DOMAINCFG_RO |
> + (value & APLIC_DOMAINCFG_WMASK);
> +
APLIC_DOMAINCFG_WMASK includes APLIC_DOMAINCFG_DM, so
the guest can clear DM through this write. But aplic.c:
aplic_init_hw_interrupts() sets the real hardware APLIC's domaincfg to IE|DM
exactly once and never touches it again. Is this expected?
Moreover, I saw that d8fbe0bbc7's commit message claims: "a guest's
domaincfg.DM reads back as a fixed one, so is there situation where we would
allow direct delivery mode? If not, the else branch should be dropped.
--
Baptiste Le Duc <baptiste.le-duc@xxxxxxxxxx>
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