Re: [Qemu-devel] [QEMU-PPC] [PATCH 11/13] target/ppc: Implement hcall H_COPY_TOFROM_GUEST

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, May 03, 2019 at 03:53:14PM +1000, Suraj Jitindar Singh wrote:
> The hcall H_COPY_TOFROM_GUEST of used by a guest acting as a nested
> hypervisor to access quadrants since quadrant access is hypervisor
> privileged.
> 
> Translate the guest address to be accessed, map the memory and perform
> the access on behalf of the guest. If the parameters are invalid, the
> address can't be translated or the memory cannot be mapped then fail
> the access.
> 
> Signed-off-by: Suraj Jitindar Singh <sjitindarsingh@gmail.com>
> ---
>  hw/ppc/spapr_hcall.c     | 74 ++++++++++++++++++++++++++++++++++++++++++++++++
>  include/hw/ppc/spapr.h   |  3 +-
>  target/ppc/mmu-radix64.c |  7 ++---
>  target/ppc/mmu-radix64.h |  4 +++
>  4 files changed, 83 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index a84d5e2163..a370d70500 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -17,6 +17,7 @@
>  #include "mmu-book3s-v3.h"
>  #include "hw/mem/memory-device.h"
>  #include "hw/ppc/ppc.h"
> +#include "mmu-radix64.h"
>  
>  static bool has_spr(PowerPCCPU *cpu, int spr)
>  {
> @@ -2158,6 +2159,78 @@ static target_ulong h_nested_tlb_invalidate(PowerPCCPU *cpu,
>      return H_SUCCESS;
>  }
>  
> +static target_ulong h_copy_tofrom_guest(PowerPCCPU *cpu,
> +                                        SpaprMachineState *spapr,
> +                                        target_ulong opcode, target_ulong *args)
> +{
> +    target_ulong lpid = args[0];
> +    target_ulong pid = args[1];
> +    vaddr eaddr = args[2];
> +    target_ulong gp_to = args[3];
> +    target_ulong gp_from = args[4];
> +    target_ulong n = args[5];
> +    int is_load = !!gp_to;

Looks like this should be a bool.

> +    void *from, *to;
> +    int prot, psize;
> +    hwaddr raddr, to_len, from_len;
> +
> +    if (spapr_get_cap(spapr, SPAPR_CAP_NESTED_KVM_HV) == 0) {
> +        return H_FUNCTION;
> +    }
> +
> +    if ((gp_to && gp_from) || (!gp_to && !gp_from)) {
> +        return H_PARAMETER;
> +    }
> +
> +    if (eaddr & (0xFFFUL << 52)) {
> +        return H_PARAMETER;
> +    }
> +
> +    if (!lpid) {
> +        return H_PARAMETER;
> +    }
> +
> +    /* Translate eaddr to raddr */
> +    if (ppc_radix64_xlate(cpu, eaddr, is_load, lpid, pid, 1, &raddr, &psize,

Don't we need some validation that the guest is in radix mode?

> +                          &prot, 0)) {
> +        return H_NOT_FOUND;
> +    }
> +    if (((raddr & ((1UL << psize) - 1)) + n) >= (1UL << psize)) {
> +        return H_PARAMETER;
> +    }
> +
> +    if (is_load) {
> +        gp_from = raddr;
> +    } else {
> +        gp_to = raddr;
> +    }
> +
> +    /* Map the memory regions and perform a memory copy */
> +    from = cpu_physical_memory_map(gp_from, &from_len, 0);
> +    if (!from) {
> +        return H_NOT_FOUND;
> +    }
> +    if (from_len < n) {
> +        cpu_physical_memory_unmap(from, from_len, 0, 0);
> +        return H_PARAMETER;
> +    }
> +    to = cpu_physical_memory_map(gp_to, &to_len, 1);
> +    if (!to) {
> +        cpu_physical_memory_unmap(from, from_len, 0, 0);
> +        return H_PARAMETER;
> +    }
> +    if (to_len < n) {
> +        cpu_physical_memory_unmap(from, from_len, 0, 0);
> +        cpu_physical_memory_unmap(to, to_len, 1, 0);
> +        return H_PARAMETER;
> +    }
> +    memcpy(to, from, n);
> +    cpu_physical_memory_unmap(from, from_len, 0, n);
> +    cpu_physical_memory_unmap(to, to_len, 1, n);
> +
> +    return H_SUCCESS;
> +}
> +
>  static spapr_hcall_fn papr_hypercall_table[(MAX_HCALL_OPCODE / 4) + 1];
>  static spapr_hcall_fn kvmppc_hypercall_table[KVMPPC_HCALL_MAX - KVMPPC_HCALL_BASE + 1];
>  
> @@ -2268,6 +2341,7 @@ static void hypercall_register_types(void)
>      spapr_register_hypercall(H_SET_PARTITION_TABLE, h_set_partition_table);
>      spapr_register_hypercall(H_ENTER_NESTED, h_enter_nested);
>      spapr_register_hypercall(H_TLB_INVALIDATE, h_nested_tlb_invalidate);
> +    spapr_register_hypercall(H_COPY_TOFROM_GUEST, h_copy_tofrom_guest);
>  
>      /* Virtual Processor Home Node */
>      spapr_register_hypercall(H_HOME_NODE_ASSOCIATIVITY,
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index 6a614c445f..d62f4108d4 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -505,7 +505,8 @@ struct SpaprMachineState {
>  #define H_SET_PARTITION_TABLE   0xF800
>  #define H_ENTER_NESTED          0xF804
>  #define H_TLB_INVALIDATE        0xF808
> -#define KVMPPC_HCALL_MAX        H_TLB_INVALIDATE
> +#define H_COPY_TOFROM_GUEST     0xF80C
> +#define KVMPPC_HCALL_MAX        H_COPY_TOFROM_GUEST
>  
>  typedef struct SpaprDeviceTreeUpdateHeader {
>      uint32_t version_id;
> diff --git a/target/ppc/mmu-radix64.c b/target/ppc/mmu-radix64.c
> index 6118ad1b00..2a8147fc38 100644
> --- a/target/ppc/mmu-radix64.c
> +++ b/target/ppc/mmu-radix64.c
> @@ -429,10 +429,9 @@ static bool validate_pate(PowerPCCPU *cpu, uint64_t lpid, ppc_v3_pate_t *pate)
>      return true;
>  }
>  
> -static int ppc_radix64_xlate(PowerPCCPU *cpu, vaddr eaddr, int rwx,
> -                             uint64_t lpid, uint64_t pid, bool relocation,
> -                             hwaddr *raddr, int *psizep, int *protp,
> -                             bool cause_excp)
> +int ppc_radix64_xlate(PowerPCCPU *cpu, vaddr eaddr, int rwx, uint64_t lpid,
> +                      uint64_t pid, bool relocation, hwaddr *raddr, int *psizep,
> +                      int *protp, bool cause_excp)
>  {
>      CPUPPCState *env = &cpu->env;
>      ppc_v3_pate_t pate;
> diff --git a/target/ppc/mmu-radix64.h b/target/ppc/mmu-radix64.h
> index 96228546aa..c0bbd5c332 100644
> --- a/target/ppc/mmu-radix64.h
> +++ b/target/ppc/mmu-radix64.h
> @@ -66,6 +66,10 @@ static inline int ppc_radix64_get_prot_amr(PowerPCCPU *cpu)
>             (iamr & 0x1 ? 0 : PAGE_EXEC);
>  }
>  
> +int ppc_radix64_xlate(PowerPCCPU *cpu, vaddr eaddr, int rwx, uint64_t lpid,
> +                      uint64_t pid, bool relocation, hwaddr *raddr, int *psizep,
> +                      int *protp, bool cause_excp);
> +
>  #endif /* TARGET_PPC64 */
>  
>  #endif /* CONFIG_USER_ONLY */

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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